1**** file PHOTOM.APX                                                                                                             
                                                                                                                                  
                   PHOTOMETRY AND POLARIMETRY NETWORK                                                                             
                                                                                                                                  
                                                                                                                                  
I. INTRODUCTION                                                                                                                   
                                                                                                                                  
	The narrow-band photometry of the Photometry and Polarimetry Network                                                             
(PPN) grew out of a previous program of narrow-band photometry of comets carried                                                  
out by M.F. A'Hearn and R.L. Millis.  That program led first to the creation in                                                   
1979 of a working group on standard filters under the auspices of Commission 15                                                   
of the International Astronomical Union.  Standard filters were defined and                                                       
purchased with a grant from the U.S. National Science Foundation for a worldwide                                                  
distribution.  These activities were merged with those of the IHW when A'Hearn                                                    
was selected as the PPN Discipline Specialist.  Since that time, a large                                                          
number of individuals have contributed at one time or another to the PPN                                                          
Network (Table I).                                                                                                                
                                                                                                                                  
                                                                                                                                  
Table I.  Discipline Specialist Team for the Photometry and Polarimetry Network                                                   
________________________________________________________________________________                                                  
                                                                                                                                  
Team Member             Affiliation                        Responsibility                                                         
________________________________________________________________________________                                                  
                                                                                                                                  
Michael F. A'Hearn      Astronomy Program                  Discipline Specialist                                                  
                        University of Maryland                                                                                    
                        College Park, MD 20742                                                                                    
                        U.S.A.                                                                                                    
                                                                                                                                  
Vladimir Vanysek	Department of Astronomy            Discipline Specialist                                                         
                        Charles University                                                                                        
                        CZ-15000 Prague 5                                                                                         
                        Czechoslovakia                                                                                            
                                                                                                                                  
Humberto Campins	Astronomy Program                  Assistant Discipline                                                          
                        University of Maryland               Specialist 1982-84                                                   
                                                                                                                                  
Michael A. Feierberg    Astronomy Program                  Assistant Discipline                                                   
                        University of Maryland               Specialist 1984-86                                                   
                                                                                                                                  
Uri Carsenty		Astronomy Program                  Assistant Discipline                                                             
                        University of Maryland               Specialist 1986-89                                                   
                                                                                                                                  
Marek Wolf 		Department of Astronomy            Assistant Discipline                                                              
                        Charles University                   Specialist                                                           
                                                                                                                                  
Wayne Osborn 		Physics Department                 Coordinator for                                                                 
                        Central Michigan University          Standard Stars                                                       
                        Mount Pleasant, MI 48859                                                                                  
                        U.S.A.                                                                                                    
                                                                                                                                  
David Edsall            Astronomy Program                  Programmer                                                             
                        University of Maryland                                                                                    
                                                                                                                                  
Jason Meyer             Astronomy Program                  Programmer                                                             
                        University of Maryland                                                                                    
                                                                                                                                  
Anne Raugh              Astronomy Program                  Programmer                                                             
                        University of Maryland                                                                                    
                                                                                                                                  
Don Ingram              Astronomy Program                  Technical Assistant                                                    
                        University of Maryland                                                                                    
                                                                                                                                  
Edward Colon            Astronomy Program                  Data Processing and                                                    
                        University of Maryland             Archiving Assistant                                                    
                                                                                                                                  
Clare Ewald             Astronomy Program                  Data Processing and                                                    
                        University of Maryland             Archiving Assistant                                                    
                                                                                                                                  
John Macuk              Astronomy Program                  Data Processing and                                                    
                        University of Maryland             Archiving Assistant                                                    
                                                                                                                                  
Mikail Shams            Astronomy Program                  Data Processing and                                                    
                        University of Maryland             Archiving Assistant                                                    
                                                                                                                                  
Edith Stahl             Astronomy Program                  Data Processing and                                                    
                        University of Maryland             Archiving Assistant                                                    
                                                                                                                                  
Lyla Taylor             Astronomy Program                  Data Processing and                                                    
                        University of Maryland             Archiving Assistant                                                    
                                                                                                                                  
Melisa Walter           Astronomy Program                  Data Processing and                                                    
                        University of Maryland             Archiving Assistant                                                    
                                                                                                                                  
Margaret Berry          Astronomy Program                  Administrative and                                                     
                        University of Maryland             Secretarial Assistant                                                  
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
	Creation of the IHW also required a broadening of the effort to include                                                          
broad-band photometry, to be emphasized when the comet was faint, and                                                             
polarimetry, to be done with the narrow-band filters in order to separate                                                         
the polarization of emission bands from that of the reflected continuum.                                                          
Narrow-band filters were therefore distributed to both photometrists and                                                          
polarimetrists.                                                                                                                   
                                                                                                                                  
	In order to ensure homogeneity of the results, an extensive effort was                                                           
made to establish a standard photometric system with a list of standard                                                           
stars distributed around the sky.  The efforts of several observers were                                                          
enlisted and the effort to combine all the observations and to establish                                                          
the standard system was led by W. Osborn.                                                                                         
                                                                                                                                  
	Realizing that many potential observers were likely to have had little                                                           
experience with cometary observations and also recognizing that the standard                                                      
photometric system might not be in final form until late in the apparition                                                        
of comet P/Halley, it was decided that final calibrations of the narrow-band                                                      
photometry would be done at the office of the Discipline Specialist at the                                                        
University of Maryland.  Ultimately, to ensure homogeneity, complete reduction                                                    
of most data was carried out at the office of the Discipline Specialist.                                                          
                                                                                                                                  
                                                                                                                                  
II. BROAD-BAND FILTERS                                                                                                            
                                                                                                                                  
        The broad-band filters that were used by many observers were obtained                                                     
by the individual observers, usually from locally available sets of filters                                                       
in the standard photometric systems.  The two standard photometric systems                                                        
that were widely used were UBVRI and the v, g, r, and i filters of the                                                            
Thuan-Gunn (1976) and Wade et al. (1979) systems.  These two systems are                                                          
indicated in the `Filter' column of the data tables as U B V R I and                                                              
VT RT GT IT respectively.  A variety of other bandpasses which do not belong                                                      
to standard systems was also used.  In general, these non-standard filters                                                        
have no designation in the `filter' column of the tables but the peak wave-                                                       
length and half-power bandwidth are given.  The only other broad-band filter                                                      
designated by name in the tables is `FES', which refers to the Fine Error                                                         
Sensor (the acquisition and tracking camera) on the International Ultraviolet                                                     
Explorer satellite.  This camera has a very broad bandpass with half-power                                                        
points at roughly 3700 and 6500 Angstroms (Sonneborn et al. 1986).                                                                
                                                                                                                                  
        We have made no attempt to reduce broad-band magnitudes from one                                                          
filter system to another because all such transformations are strongly                                                            
dependent on the spectrum of the object being studied.  Although empirical                                                        
transformations exist for stellar spectra, they are totally inappropriate                                                         
for cometary spectra.  At times when the comet was inactive, the transfor-                                                        
mations may be approximately valid although even then this is not clear since                                                     
reddening of the solar continuum by the cometary nucleus and/or dust is                                                           
not equivalent to changing the spectrum to that of a cooler star.                                                                 
                                                                                                                                  
                                                                                                                                  
III. NARROW-BAND FILTERS                                                                                                          
                                                                                                                                  
	The narrow-band filters that were distributed to both photometrists                                                              
and polarimetrists came from several different manufacturers. Although the                                                        
manufacturers tried to maintain uniformity among the filters, they were not                                                       
entirely successful. Since the transformations from measured magnitudes to                                                        
fluxes depend on the actual profiles of the filters, the differences among the                                                    
transmission profiles of the different filters are discussed.                                                                     
                                                                                                                                  
	It should be kept in mind that the characteristics of the bandpasses                                                             
of interference filters change with time, some much more than others. All                                                         
measurements reported here are based on data taken prior to distribution                                                          
of the filters, that is, around 1982-83, except for the profile of the OH                                                         
filter which was remeasured in 1988 and the profiles of the NH filters which                                                      
were measured by the manufacturer in 1979.  We are aware of some changes in                                                       
the bandpasses since some observers measured the bandpasses themselves and                                                        
reported problems to us.  At least one of the OH filters has had a significant                                                    
shift in the bandpasss reported to us and several of the CN filters (all so                                                       
far from the batch manufactured by MicroCoatings, Inc.) have shown a                                                              
significant (5-10 Angstrom) shift toward longer wavelengths.  These changes                                                       
will have rather little effect on the observations of stars, other than for                                                       
the linearization of the extinction for the OH filter, but they will have                                                         
drastic effects on the transformation of cometary magnitudes to fluxes.  Any                                                      
observers planning to continue to use the filters in the future should take                                                       
care to have the bandpass remeasured regularly.                                                                                   
                                                                                                                                  
	Because the OH and NH filters are treated differently from the                                                                   
remainder, the tabular data are included in the section with the                                                                  
writeup. For the remaining filters, the tabular data are all at the end                                                           
of this section. All filters are identified by the nominal central                                                                
wavelength [A], the nominal FWHM [A], and a serial number consisting of a                                                         
letter indicating the manufacturer plus a sequential number.                                                                      
                                                                                                                                  
     A graphical representation of the relationship between the narrow-band                                                       
filters and the spectrum of a typical comet can be found in Figure 1 of                                                           
the chapter by M. F. A'Hearn in the IHW Summary Volume.  There the                                                                
transmission curves of the filters are superimposed on a spectrum of                                                              
comet P/Tuttle kindly provided by S. M. Larson.  That spectrum is a                                                               
combination of ground-based data and data obtained with the IUE satellite.                                                        
The two speectra have been scaled to approximately account for the                                                                
difference in field-of-view of the two instruments.  The species being                                                            
measured are also indicated in that figure.                                                                                       
                                                                                                                                  
                                                                                                                                  
A. OH (3085A)                                                                                                                     
                                                                                                                                  
	This filter was designed to measure the 0-0 band of the A-X                                                                      
system of OH. Although the 1-1 band is in the wing of the filter, it does                                                         
not contribute a large fraction of the total light. The formula for flux                                                          
in Section IV.B gives the flux in the 0-0 band alone. These filters                                                               
were all manufactured by Spectro-Film, Inc. of Winchester, Mass.,                                                                 
and are, in a sense, a special case because the primary bandpass is                                                               
centered near 3075A with a full-width-half-maximum FWHM = 80A but there                                                           
is also a secondary bandpass near 3580A which is lower in transmission                                                            
by more than two orders of magnitude but wider by about one order of                                                              
magnitude. It thus transmits, for a flat spectrum, a flux of a few percent                                                        
that of the primary bandpass. This secondary bandpass, however, is the                                                            
dominant source of light at large airmasses because the atmospheric                                                               
transmission is so much greater at the wavelength of the secondary bandpass                                                       
than at the wavelength of the primary bandpass.  Data were received from                                                          
only a few observers using these filters and the following data, which                                                            
are for the filter used by the group from Lowell Observatory, can be                                                              
considered representative.  Spectro-Film made the filters in two separate                                                         
evaporation runs and it appears that filters are very well matched within                                                         
a single evaporation run but that there are some noticeable differences                                                           
between the two evaporation runs.                                                                                                 
                                                                                                                                  
                                                                                                                                  
Table II. Transmission Curve of the OH Filter 3085/75 (#S2)                                                                       
________________________________________________________________________________                                                  
                                                                                                                                  
Lambda   Trans.      Lambda   Trans.      Lambda   Trans.      Lambda   Trans.                                                    
 [A]                  [A]                  [A]                  [A]                                                               
________________________________________________________________________________                                                  
                                                                                                                                  
 2920   .000020       3090   .36125        3270   .0001375      3580   .002850                                                    
 2930   .0000285      3100   .33125        3280   .000110       3590   .00275                                                     
 2940   .000050       3110   .24125        3290   .0000975      3600   .00255                                                     
 2950   .0001075      3120   .12125        3300   .00008        3620   .002275                                                    
 2960   .000225       3130   .0500         3320   .000055       3640   .002100                                                    
 2970   .000485       3140   .02125        3340   .0000475      3660   .0020875                                                   
 2980   .00095        3150   .010          3360   .0000375      3680   .0020                                                      
 2990   .0020         3160   .00570        3380   .00003375     3700   .0018625                                                   
 3000   .0045         3170   .00325        3400   .0000325      3720   .0016625                                                   
 3010   .01125        3180   .002025       3420   .0000375      3740   .001375                                                    
 3020   .03           3190   .001325       3440   .000050       3760   .0010375                                                   
 3030   .095          3200   .000925       3460   .0000925      3780   .000750                                                    
 3040   .25           3210   .00065        3480   .0001025      3800   .0004875                                                   
 3050   .385          3220   .000473       3500   .000275       3820   .0002875                                                   
 3054   .3950         3230   .000360       3520   .0005375      3840   .00015                                                     
 3060   .38875        3240   .000285       3540   .0012125      3860   .0000575                                                   
 3070   .3775         3250   .000215       3560   .0022875      3880   .000015                                                    
 3080   .37375        3260   .000175       3570   .0027375      3900   .0000025                                                   
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
B. NH (3365A)                                                                                                                     
                                                                                                                                  
	The filters for NH were not distributed as part of the IHW effort                                                                
but several older filters were available from previous programs. These                                                            
filters were used at Lowell Observatory, at Cerro Tololo Inter-American                                                           
Observatory, and at Perth Observatory. They were chosen to measure the                                                            
delta-v = 0 sequence of the A-X system of NH. Although the entire                                                                 
sequence is in the bandpass, virtually all of the light is from the 0-0                                                           
band because the Franck-Condon factors are low for the other bands. These                                                         
filters were also manufactured by Spectro-Film, Inc., although many years                                                         
before the OH filters. Since the NH filters are not very well matched,                                                            
the only way to characterize them is to present the transmission curve                                                            
for each of them (Table III).                                                                                                     
                                                                                                                                  
                                                                                                                                  
Table III. Transmission Curves of the NH Filters 3365/70                                                                          
________________________________________________________                                                                          
                                                                                                                                  
                             Transmission                                                                                         
Lambda    ______________________________________________                                                                          
 [A]                                                                                                                              
              Filter #S1      Filter #S2      Filter #S3                                                                          
________________________________________________________                                                                          
                                                                                                                                  
 3200            .002            .002            .001                                                                             
 3225	         .002  	         .002            .002                                                                               
 3250            .003            .003            .002                                                                             
 3275            .005            .005            .003                                                                             
 3300            .012            .010            .010                                                                             
 3325            .088            .082            .058                                                                             
 3350            .310            .300            .265                                                                             
 3375            .375            .368            .332                                                                             
 3400            .225            .240            .290                                                                             
 3425            .045            .050            .080                                                                             
 3450            .010            .011            .013                                                                             
 3475            .004            .003            .003                                                                             
 3500            .002       	 .002            .002                                                                                
________________________________________________________                                                                          
                                                                                                                                  
                                                                                                                                  
C. Continuum 3650A                                                                                                                
                                                                                                                                  
	The early filters of this type were produced by MicroCoatings, Inc.                                                              
of Burlington, Mass. while the later ones were produced by Andover Corp. of                                                       
Lawrence, Mass. Approximately 75 were distributed. Since the two companies                                                        
used different techniques to manufacture the filters, the characteristics                                                         
came out rather different. Although the filter is intended for the                                                                
continuum, there are some weak ionic bands present in the wings of the                                                            
filter. Preliminary calculations show that the contamination by these                                                             
ions (CO+ and CO2+) is not significant.                                                                                           
                                                                                                                                  
D. CN (3871A)                                                                                                                     
                                                                                                                                  
       	This filter is intended to measure the delta-v = 0 sequence of the                                                        
B-X system of CN. Like the 3650 filters, the early ones were made by                                                              
MicroCoatings, Inc., the later ones by Andover Corp. The entire                                                                   
delta-v = 0 sequence is included but since the 1-1 band is weaker than                                                            
the 0-0 band by a full order of magnitude, the flux is 90% due to the                                                             
0-0 band. The reduction formulae in Section IV.B give the flux in the                                                             
complete delta-v = 0 sequence.                                                                                                    
                                                                                                                                  
E. C3 (4060A)                                                                                                                     
                                                                                                                                  
        This filter is intended to measure a portion of the A-X Swings                                                            
system of C3 which extends over approximately 150A in this region. The                                                            
filter was chosen to measure that portion of the emission band that is least                                                      
contaminated by other features (at the short wavelengths by the strongest                                                         
of the CO+ bands).  The reduction formulae in Section IV.B, however, are                                                          
for the flux integrated over the entire band, based on published profiles                                                         
which are assumed to remain the same in all comets. These filters were                                                            
also manufactured both by MicroCoatings, Inc. and by Andover Corp.                                                                
                                                                                                                                  
F. CO+ (4260A)                                                                                                                    
                                                                                                                                  
        Since the strongest band of CO+, the 3-0 band, is inextricably in-                                                        
volved with the C3 band, this filter was chosen to cover the 2-0 band of                                                          
the A-X system. These filters were all made by Barr Associates, Inc., of                                                          
Westford, Mass. Our results indicate a strong sensitivity to the subtraction                                                      
of continuum relative to which the emission band is weak except in distant                                                        
parts of the ion tail.                                                                                                            
                                                                                                                                  
G. Continuum 4845A                                                                                                                
                                                                                                                                  
        This region of the continuum is noticeably contaminated by the                                                            
high vibrational and rotational components of the delta-v = 0 sequence of                                                         
C2 which is predominantly at longer wavelengths. Our standard reduction                                                           
corrects for this contamination.  The filters were manufactured by                                                                
MicroCoatings, Inc. and by Andover Corp.                                                                                          
                                                                                                                                  
H. C2 (5140A)                                                                                                                     
                                                                                                                                  
        This filter measures the delta-v = 0 sequence of the Swan (d-a)                                                           
system of C2. The filters were manufactured both by MicroCoatings, Inc.                                                           
and by Andover Corp.                                                                                                              
                                                                                                                                  
J. Continuum 6840A                                                                                                                
                                                                                                                                  
        This filter also measures a relatively 'clean' region of the                                                              
continuum. There is some weak emission by NH2 in this region but it does                                                          
not appear to be a significant contributor. Because this band includes                                                            
the Fraunhofer line B, which is due to telluric oxygen, there is a                                                                
possibility that atmospheric extinction in this band might be affected                                                            
by curve-of-growth effects. No allowance has been made for this in our                                                            
reductions. The most obvious alternative location for a red continuum                                                             
filter would involve interference from the telluric water vapor absorption                                                        
and would cause greater problems because of the variation of humidity.                                                            
These filters were all manufactured by Barr Associates, Inc.                                                                      
                                                                                                                                  
K. H2O+ (7000A)                                                                                                                   
                                                                                                                                  
        This filter was chosen to isolate the (0,6,0)-(0,0,0) band of H2O+.                                                       
Because this band is very broad and the filter was designed to encompass                                                          
all of it, the bandpass tends to be dominated by continuum in the                                                                 
head of many comets and the deduced flux is therefore sensitive to the                                                            
precison of the subtraction of continuum. There is also some contamination                                                        
by an emission band of NH2. The filters were all manufactured by                                                                  
Barr Associates, Inc.                                                                                                             
                                                                                                                                  
	Characteristics of all the filters except those for OH and NH are                                                                
given in Table IV.  Each filter is identified by its peak wavelength, FWHM                                                        
(following a slash), and the manufacturer.  Listed are the mean and, in (),                                                       
the rms scatter for the peak wavelength, the peak transmission, and the full                                                      
widths at 80%, 50%, 10%, and 1% of peak transmission.  Table V presents the                                                       
full widths for several actual filters--the overall narrowest one (Nr.),                                                          
an average (Av.), and the widest (Wd.).  The numbers in () are the most                                                           
extreme values found.  Table VI shows the complete profile for one filter                                                         
of each type.  In Tables V and VI the individual filters are identified by                                                        
the manufacturer (M = MicroCoatings, Inc.; A = Andover Corp.; B = Barr Asso-                                                      
ciates) and its assigned number.                                                                                                  
                                                                                                                                  
                                                                                                                                  
Table IV. Average Characteristics of the IHW Narrow-Band Filters                                                                  
________________________________________________________________________________                                                  
                                                                                                                                  
 Filter      Lambda      Trans.    Width(80%)  Width(50%)  Width(10%)  Width(1%)                                                  
[A]/[A]       [A]                      [A]         [A]         [A]        [A]                                                     
________________________________________________________________________________                                                  
                                                                                                                                  
3650/80                                                                                                                           
 Mic.     3650.1(5.5)  .368(.050)   57.7(4.3)   82.5(3.4)   126(4.8)   191(6.5)                                                   
 And.     3644.2(4.1)  .295(.029)   68.3(1.3)   88.1(1.7)   125(2.9)   180(4.0)                                                   
                                                                                                                                  
3871/50                                                                                                                           
 Mic.     3871.6(2.7)  .264(.030)   31.3(4.4)   44.2(3.9)    70(5.6)   115(8.4)                                                   
 And.     3870.2(2.3)  .312(.031)   30.4(0.6)   42.4(1.4)    64(2.2)    92(1.2)                                                   
                                                                                                                                  
4060/70                                                                                                                           
 Mic.     4057.9(2.0)  .458(.009)   62.6(1.9)   76.7(2.0)   100(3.5)   137(5.0)                                                   
 And.     4054.1(1.8)  .487(.020)   59.1(3.5)   70.5(2.9)    91(1.3)   117(2.3)                                                   
                                                                                                                                  
4260/65                                                                                                                           
 Barr     4259.8(5.8)  .445(.009)   62.1(1.4)   69.8(0.4)    76(0.5)    79(1.6)                                                   
                                                                                                                                  
4845/65                                                                                                                           
 Mic.     4848.1(5.6)  .721(.009)   56.9(1.9)   71.7(1.0)   100(1.6)   143(2.8)                                                   
 And.     4849.0(1.1)  .739(.008)   52.4(1.0)   65.0(0.6)    90(0.4)                                                              
                                                                                                                                  
5140/90                                                                                                                           
 Mic.     5140.4(5.2)  .629(.010)   74.2(3.5)   85.3(2.2)   108(1.7)   142(3.3)                                                   
 And.     5141.3(4.5)  .739(.017)   71.3(2.7)   82.6(4.2)   106(5.4)   155                                                        
                                                                                                                                  
6840/90                                                                                                                           
 Barr     6840.3(15.)  .788(.016)   79.9(4.9)   90.9(4.4)   114(4.2)   146(5.4)                                                   
                                                                                                                                  
7000/175                                                                                                                          
 Barr     7025.9(3.6)  .791(.013)    215(1.3)    228(1.2)   259(2.2)   311(2.7)                                                   
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
Table V. Characteristics of Filters--Narrowest, Average, and Widest                                                               
____________________________________________________________________                                                              
                                                                                                                                  
 Filter  Desc. Ident.  Width(80%)  Width(50%)  Width(10%)  Width(1%)                                                              
[A]/[A]                   [A]         [A]         [A]         [A]                                                                 
____________________________________________________________________                                                              
                                                                                                                                  
3650/80   Nr.   M32      54(49)      79         123(121)    184(182)                                                              
          Av.   M 3      57          81         125                                                                               
          Wd.   M37      67          88(89)     128(137)    201                                                                   
          Nr.   A36      66(65)      88(86)     126(114)    169                                                                   
          Av.   A30      68          87         124         181                                                                   
          Wd.   A34      68(72)      90(92)     127(129)    183(184)                                                              
                                                                                                                                  
3871/50   Nr.   M30      28(21)      41(38)      63(62)      98                                                                   
          Av.   M41      31          44          71         118                                                                   
          Wd.   M43      35(46)      49(50)      77(82)     125(127)                                                              
          Nr.   A26      30(29)      42(40)      62(61)      90                                                                   
          Av.   A17      30          42          64          92                                                                   
          Wd.   A13      31          42          73            (94)                                                               
                                                                                                                                  
4060/70   Nr.   M49      60(58)      72          92         130                                                                   
          Av.   M25      63          77         101                                                                               
          Wd.   M38      64(65)      78(80)     104         144(146)                                                              
          Nr.   A33      53          59          89         116(111)                                                              
          Av.   A22      59          70          91         117                                                                   
          Wd.   A14      64          74          92(93)        (120)                                                              
                                                                                                                                  
4260/65   Nr.   B10      61          69          76(75)      78(77)                                                               
          Av.   B 4      63          70          76          78                                                                   
          Wd.   B25      63(64)      70          76          83                                                                   
                                                                                                                                  
4845/65   Nr.   M25      51          70(69)      99(98)        (139)                                                              
          Av.   M21      57          73         100         143                                                                   
          Wd.   M33      59(60)      73         101(109)    148                                                                   
          Nr.   A22      51          64          91                                                                               
          Av.   A12      52          65          90                                                                               
          Wd.   A17      52(54)      66          90(91)                                                                           
                                                                                                                                  
5140/90   Nr.   M14      56          80         104            (137)                                                              
          Av.   M41      74          86         108         141                                                                   
          Wd.   M36      79          90         113         148                                                                   
          Nr.   A14      68          80         103                                                                               
          Av.   A20      71          81         104                                                                               
          Wd.   A29      77          92         118         155                                                                   
                                                                                                                                  
6840/90   Nr.   B23      68          83         110         141                                                                   
          Av.   B21      80          92         115         148                                                                   
          Wd.   B54      94          95         120         152                                                                   
                                                                                                                                  
7000/175  Nr.   B 3     215(211)    227         256         307                                                                   
          Av.   B51     216         229         258         309                                                                   
          Wd.   B15     217         229(232)    260(263)    320                                                                   
____________________________________________________________________                                                              
                                                                                                                                  
                                                                                                                                  
Table VI. Transmission Curves of Actual Filters                                                                                   
_____________________________________________________________                                                                     
                                                                                                                                  
Lambda Trans.   Lambda Trans.   Lambda Trans.   Lambda Trans.                                                                     
 [A]             [A]             [A]             [A]                                                                              
_____________________________________________________________                                                                     
                                                                                                                                  
                     Filter: 3650/80; M30                                                                                         
                                                                                                                                  
 3522  .00152    3587  .08181    3652  .3030     3717  .0237                                                                      
 3527  .00167    3592  .1169     3657  .3030     3722  .0130                                                                      
 3532  .00200    3597  .1515     3662  .3030     3727  .0079                                                                      
 3537  .00222    3602  .2030     3667  .3006     3732  .00303                                                                     
 3542  .00242    3607  .2424     3672  .2912     3737  .00285                                                                     
 3547  .00258    3612  .2783     3677  .2424     3742  .00278                                                                     
 3552  .00303    3617  .2912     3682  .20907    3747  .00248                                                                     
 3557  .00576    3622  .2936     3687  .1515     3752  .00222                                                                     
 3562  .00788    3627  .29827    3692  .1224     3757  .00217                                                                     
 3567  .00939    3632  .3013     3697  .0821     3762  .00203                                                                     
 3572  .02275    3637  .3013     3702  .0559     3767  .00192                                                                     
 3577  .02908    3642  .3030     3707  .0297     3772  .00152                                                                     
 3582  .0303     3647  .3030     3712  .0266                                                                                      
                                                                                                                                  
                     Filter: 3871/50; A16                                                                                         
                                                                                                                                  
 3802  .00033    3842  .03343    3882  .3316     3922  .04072                                                                     
 3807  .00078    3847  .08311    3887  .3343     3927  .02804                                                                     
 3812  .00147    3852  .1327     3892  .3289     3932  .02117                                                                     
 3817  .00207    3857  .1932     3897  .3049     3937  .00669                                                                     
 3822  .00289    3862  .2474     3902  .2675     3942  .00319                                                                     
 3827  .00613    3867  .2835     3907  .2163     3947  .00215                                                                     
 3832  .01297    3872  .3129     3912  .1488     3952  .00152                                                                     
 3837  .02609    3877  .3236     3917  .09772    3957  .00078                                                                     
                                                 3962  .00033                                                                     
                     Filter: 4060/70; A22                                                                                         
                                                                                                                                  
 3972  .00026    4012  .1592     4052  .512      4092  .2326                                                                      
 3977  .00038    4017  .256      4057  .5079     4097  .1335                                                                      
 3982  .00051    4022  .3911     4062  .5038     4102  .0512                                                                      
 3987  .00187    4027  .4628     4067  .49152    4107  .02638                                                                     
 3992  .00359    4032  .4833     4072  .49152    4112  .00512                                                                     
 3997  .00512    4037  .4997     4077  .49152    4117  .00051                                                                     
 4002  .02638    4042  .5079     4082  .45056    4122  .00038                                                                     
 4007  .0512     4047  .512      4087  .3873     4127  .00026                                                                     
                                                                                                                                  
                     Filter: 4260/65; B4                                                                                          
                                                                                                                                  
 4200  .001      4230  .390      4260  .445      4290  .351                                                                       
 4205  .002      4235  .393      4265  .439      4295  .199                                                                       
 4210  .007      4240  .404      4270  .430      4300  .071                                                                       
 4215  .021      4245  .427      4275  .422      4305  .022                                                                       
 4220  .084      4250  .442      4280  .415      4310  .008                                                                       
 4225  .261      4255  .447      4285  .405      4315  .003                                                                       
                                                 4320  .001                                                                       
                     Filter: 4845/65; M21                                                                                         
                                                                                                                                  
 4714  .00042    4779  .02952    4844  .6833     4909  .04197                                                                     
 4719  .00048    4784  .03959    4849  .6778     4914  .03557                                                                     
 4724  .00052    4789  .04726    4854  .6669     4919  .02459                                                                     
 4729  .00056    4794  .06087    4859  .6505     4924  .01342                                                                     
 4734  .00066    4799  .1084     4864  .6450     4929  .00664                                                                     
 4739  .00104    4804  .2317     4869  .6286     4934  .00374                                                                     
 4744  .00194    4809  .3178     4874  .5739     4939  .00282                                                                     
 4749  .00274    4814  .4677     4879  .4481     4944  .00200                                                                     
 4754  .00425    4819  .5849     4884  .3178     4949  .00131                                                                     
 4759  .00508    4824  .6395     4889  .2287     4454  .00100                                                                     
 4764  .00629    4829  .6559     4894  .1084     4459  .00076                                                                     
 4769  .01140    4834  .6724     4899  .06320    4464  .00066                                                                     
 4774  .01781    4839  .6833     4904  .05039    4969  .00044                                                                     
                                                 4974  .00042                                                                     
                     Filter: 5140/90; M5                                                                                          
                                                                                                                                  
 5030  .00017    5099  .3945     5144  .6109     5189  .1660                                                                      
 5034  .00020    5104  .5649     5149  .6039     5194  .08551                                                                     
 5044  .00030    5109  .5598     5154  .6067     5204  .02393                                                                     
 5054  .00054    5114  .5408     5159  .6166     5214  .00724                                                                     
 5064  .00137    5119  .5546     5164  .6295     5224  .00254                                                                     
 5074  .00521    5124  .5875     5169  .6194     5234  .00122                                                                     
 5084  .02786    5129  .6166     5174  .5623     5244  .00065                                                                     
 5089  .07112    5134  .6310     5179  .4446     5254  .00041                                                                     
 5094  .1862     5139  .6237     5184  .2858     5264  .00027                                                                     
                                                 5271  .00021                                                                     
                     Filter: 6840/90; B21                                                                                         
                                                                                                                                  
 6750  .00000    6795  .43956    6840  .81500    6885  .45000                                                                     
 6755  .00400    6800  .65919    6845  .81100    6890  .25000                                                                     
 6760  .00600    6805  .77105    6850  .80700    6895  .11985                                                                     
 6765  .00800    6810  .79502    6855  .79901    6900  .05990                                                                     
 6770  .02000    6815  .79901    6860  .79303    6905  .03196                                                                     
 6775  .02796    6820  .79901    6865  .79102    6910  .01598                                                                     
 6780  .05992    6825  .80700    6870  .79000    6915  .08000                                                                     
 6785  .08000    6830  .81100    6875  .77000    6920  .00400                                                                     
 6790  .23970    6835  .81200    6880  .66000    6925  .00023                                                                     
                                                 6930  .00000                                                                     
                     Filter: 7000/175; B7                                                                                         
                                                                                                                                  
 6850  .003      6940  .746      7030  .826      7120  .791                                                                       
 6855  .004      6945  .748      7035  .825      7125  .752                                                                       
 6860  .005      6950  .756      7040  .825      7130  .610                                                                       
 6865  .007      6955  .770      7045  .826      7135  .418                                                                       
 6870  .010      6960  .783      7050  .827      7140  .249                                                                       
 6875  .015      6965  .794      7055  .825      7145  .142                                                                       
 6880  .022      6970  .801      7060  .823      7150  .080                                                                       
 6885  .036      6975  .806      7065  .820      7155  .048                                                                       
 6890  .060      6980  .808      7070  .809      7160  .029                                                                       
 6895  .102      6985  .809      7075  .793      7165  .018                                                                       
 6900  .177      6990  .812      7080  .773      7170  .011                                                                       
 6905  .300      6995  .814      7085  .748      7175  .008                                                                       
 6910  .475      7000  .816      7090  .726      7180  .006                                                                       
 6915  .475      7005  .819      7095  .711      7185  .004                                                                       
 6920  .753      7010  .822      7100  .706      7190  .003                                                                       
 6925  .780      7015  .823      7105  .715      7195  .002                                                                       
 6930  .769      7020  .824      7110  .735      7200  .001                                                                       
 6935  .754      7025  .825      7115  .772                                                                                       
_____________________________________________________________                                                                     
                                                                                                                                  
                                                                                                                                  
IV. STANDARD STARS                                                                                                                
                                                                                                                                  
A. Standards for Broad-Band Photometry                                                                                            
                                                                                                                                  
        No special efforts were made to establish any standards for broad-                                                        
band photometry since the commonly used systems already have extensive                                                            
networks of standard stars.  In the individual FITS files for each set of                                                         
observations we have included, for those cases in which we had the information,                                                   
a HISTORY keyword which lists the standard stars that were used in the                                                            
observational program.  We have not always had available the actual                                                               
magnitudes used for the standard stars and, in any case, different observers                                                      
tend to use slightly different standard values for the same star.  For                                                            
those reasons we have not provided a complete table of the broad-band                                                             
magnitudes of the standard stars.  In those cases in which we know the                                                            
values used by the observers, we have included those values in the FITS                                                           
files under the HISTORY keyword.                                                                                                  
                                                                                                                                  
B. Standards for Narrow-Band Photometry                                                                                           
                                                                                                                                  
	An extensive set of standard stars was defined using the narrow-band                                                             
filters distributed by the IHW.  Primary standard stars were chosen to be of                                                      
two types: solar analogs and stars of spectral types O9-B3.  The early-type                                                       
stars were chosen to have the most line-free spectra and to be distributed                                                        
along the celestial equator while the solar analogs were chosen to be                                                             
those most nearly like the Sun in the work of Hardorp (1978, 1980a,b, 1982).                                                      
The solar analogs were used to determine the continuum underlying the                                                             
emission bands of the comet and are marked in the table below.  Secondary                                                         
standards were chosen in other parts of the sky, particularly near the path                                                       
of P/Halley.                                                                                                                      
                                                                                                                                  
	 Observations were obtained at several sites using different sets                                                                
of the standard filters and different photometers.  The observations were                                                         
synthesized by W. Osborn to establish the standard magnitudes.  The zero-                                                         
point of the system was arbitrarily set to be m = 5.88 for all filters for the                                                    
star 53 Psc = HD 3379 (V = 5.88).  Empirically there appears to be nothing                                                        
more than a zero point shift between instrumental magnitudes and the standard                                                     
magnitudes in nearly all cases.  In a few cases, that is, for certain sets of                                                     
filters, the zero point shift of the CN filter is slightly different for                                                          
G-stars and for B-stars and presumably, therefore, for comets.  For a more                                                        
complete discussion, see the paper by Osborn et al. (1990).                                                                       
                                                                                                                                  
                                                                                                                                  
Table VII. The Set of Standard Stars for Narrow-Band Photometry                                                                   
__________________________________________________________________________________________________________                        
                                                                                                                                  
                                          Monochromatic Magnitude at Wavelength [A]                                               
  HD#     R.A.(1950)Decl    --------------------------------------------------------------------  Spectrum                        
                             3085   3365   3650   3871   4060   4260   4845   5140   6840   7000                                  
__________________________________________________________________________________________________________                        
                                                                                                                                  
  3379 00 34 10.8 +14 57 24  5.880  5.880  5.880  5.880  5.880  5.880  5.880  5.880  5.880  5.880 B2.5IV *                        
 10126 01 36 45.6  27 51 22 10.497  9.768  9.304  9.727  8.978  8.863  8.011  7.999  7.11   7.09  G8V                             
 13974 02 13 59.6  33 59 48  7.069  6.494  6.141  6.252  5.902  5.811  5.130  5.096  4.290  4.25  G0V                             
 16397 02 35 30.9  30 36 24  9.532  8.943  8.559  8.683  8.340  8.265  7.596  7.546  6.81   6.87  G1V                             
 16908 02 40 30.7  27 29 44  4.735  4.742  4.725  4.677  4.676  4.677  4.668  4.665  4.626  4.641 B3V                             
 18803 02 59 27.7  26 24 56  9.349  8.600  8.149  8.565  7.826  7.704  6.898  6.864  6.033  6.005 G8V                             
 22951 03 39 12.0  33 48 22  4.925  4.932  4.893  5.107  5.161  5.146  5.017  5.023  4.862  4.892 B0.5V                           
 23464 03 43 15.2  22 58 28 11.08  10.46  10.011 10.196  9.723  9.598  8.960  8.892         8.11  G0V                             
 24760 03 54 29.4  39 52 03  2.433  2.529  2.549  2.807  2.933  2.948  2.885  2.952  2.885  2.956 B0.5V                           
 25680 04 02 22.4  21 52 32  8.289  7.665  7.277  7.484  6.987  6.868  6.163  6.108  5.340  5.326 G5V                             
 26736 04 11 32.2  23 27 02 10.581  9.896  9.472  9.732  9.178  9.055  8.318  8.269  7.433  7.360 G3V                             
 26912 04 12 49.0  08 46 07  4.669  4.593  4.539  4.411  4.404  4.399  4.329  4.317  4.202  4.202 B3IV   *                        
 28099 04 23 47.7  16 38 07 10.631  9.958  9.547  9.823  9.227  9.097  8.364  8.312  7.51   7.48  G6V    +                        
 29461 04 36 07.6  14 00 29 10.454  9.839  9.410  9.675  9.097  8.973  8.243  8.196  7.370  7.324 G5V    +                        
 30246 04 43 38.9  15 22 59 10.861 10.170  9.767 10.053  9.456  9.340  8.585  8.539         7.68  G5V    +                        
 30455 04 45 46.3  18 37 40  9.16   8.69   8.297  8.464  8.004  7.921  7.218  7.160  6.36   6.32  G2V                             
 31966 04 57 43.5  14 18 36         8.66   8.245  8.476  7.895  7.781  7.038  6.979  6.15   6.10  G2IV-V                          
 36351 05 28 37.0  03 15 21  5.187  5.229  5.248  5.383  5.426  5.439  5.419  5.444  5.436  5.452 B1.5V                           
 41753 06 04 42.9  14 46 34  4.43   4.41   4.408  4.382  4.393  4.405  4.403  4.410  4.404  4.426 B3V                             
 44594 06 18 47.1 -48 42 50  9.110  8.496  8.051  8.319  7.726  7.613  6.889  6.832  6.011  5.977 G2V    +                        
 47032 06 34 07.4  04 44 14  9.776  9.57   9.396  9.577  9.594  9.516  9.116  8.984  8.303  8.260 B2                              
 52266 06 57 53.9 -05 45 21  7.053  7.075  7.037  7.327  7.415  7.404  7.240  7.256  7.040  7.048 O9V    *                        
 74280 08 40 36.7  03 34 46  4.196  4.206  4.198  4.240  4.265  4.283  4.275  4.293  4.296  4.324 B4V    *                        
 76151 08 51 50.1 -05 14 39  8.525  7.898  7.462  7.810  7.152  7.044  6.291  6.238  5.404  5.371 G3V                             
 84971 09 46 12.4 -02 28 50  8.579  8.597  8.583  8.620  8.665  8.679  8.629  8.660  8.612  8.631 B2.5V                           
 88725 10 11 32.1  03 24 19  9.970  9.413  9.003  9.145  8.791  8.720  8.020  7.963  7.152  7.117 G1V                             
 89688 10 18 27.1  02 32 31  6.838  6.802  6.756  6.734  6.766  6.761  6.671  6.682  6.584  6.596 B2.5IV *                        
 96700 11 05 31.5 -29 54 07  8.815  8.242  7.845  7.995  7.569  7.480  6.803  6.733  5.949  5.917 G2V                             
 97991 11 13 38.6 -03 11 57  6.943  7.038  7.055  7.283  7.348  7.374  7.355  7.401  7.421  7.446 B1V                             
 99171 11 21 58.1 -42 23 39  5.924  5.989  5.975  6.087  6.118  6.132  6.115  6.141  6.129  6.152 B2V                             
104337 11 58 17.5 -19 22 50  4.955  5.019  5.028  5.193  5.256  5.277  5.240  5.283  5.283  5.312 B1.5V                           
105590 12 06 53.2 -11 34 36  9.365  8.727  8.296  8.593  8.000  7.890  7.141  7.089  6.248  6.216 G2V    +                        
112185 12 51 50.1 +56 13 51  3.23   3.02   2.84   2.10   1.98   1.93   2.00   1.89   1.59   1.65  B2                              
120086 13 44 44.2 -02 11 40  7.653  7.697  7.695  7.813  7.855  7.862  7.845  7.873  7.867  7.888 B3III  *                        
120315 13 45 34.3  49 33 44  1.89   1.90   1.91   1.90   1.91   1.91   1.94   1.94   1.86   1.89  B3V    *                        
121849 13 55 42.9 -33 45 15 10.743 10.024  9.614  9.874  9.339  9.256  8.466  8.421  7.542  7.506 G5V                             
122980 14 02 59.0 -40 56 28  4.159  4.161  4.188  4.301  4.325  4.334  4.342  4.358  4.365  4.386 B2V                             
124580 14 12 27.6 -44 46 00  8.593  8.014  7.644  7.769  7.390  7.285  6.624  6.550  5.773  5.745 G1V                             
133955 15 05 27.9 -45 05 20  4.054  4.017  4.035  4.062  4.060  4.066  4.075  4.065  4.049  4.054 B3V                             
136352 15 18 25.2 -48 08 06  8.062  7.425  7.012  7.221  6.754  6.673  5.944  5.896  5.066  5.033 G2V                             
137432 15 24 05.5 -36 35 37  5.600  5.570  5.561  5.504  5.472  5.475  5.492  5.455  5.416  5.437 B4V                             
148045 16 24 27.7 -56 34 03 10.83         10.07   9.86   9.61   9.48   9.06   8.94   8.32   8.31  G0V                             
149363 16 31 47.9 -06 01 59  7.770  7.752  7.706  7.938  8.027  8.007  7.818  7.823  7.590  7.600 B0.5III*                        
149438 16 32 45.9 -28 06 51  2.26   2.281  2.340  2.656  2.767  2.801  2.780  2.820  2.84   2.89  B0V                             
164852 18 00 14.7  20 49 57  5.443  5.398  5.372  5.337  5.323  5.317  5.292  5.269  5.186  5.208 B3V    *                        
165185 18 03 00.9 -36 01 32  8.207  7.648  7.245  7.381  6.988  6.874  6.212  6.139  5.374  5.352 G5V                             
166197 18 07 36.8 -33 48 40  5.903  5.956  5.932  6.104  6.184  6.190  6.113  6.154  6.081  6.106 B1V                             
175191 18 52 09.9 -26 21 38  1.955  1.95   1.955  2.02   2.045  2.065  2.09   2.09   1.92   1.95  B2.5V                           
186427 19 40 32.0  50 24 03  8.779  8.093  7.671  7.946  7.350  7.240  6.492  6.451  5.616  5.635 G5V    +                        
189340 19 57 04.3 -10 05 25  8.094  7.518  7.170  7.249  6.882  6.768  6.138  6.075  5.315  5.296 G0V                             
191263 20 06 15.1  10 34 44  6.430  6.410  6.390  6.366  6.365  6.364  6.347  6.346  6.302  6.328 B3IV   *                        
191639 20 08 27.5 -08 59 30  6.099  6.159  6.153  6.394  6.486  6.495  6.423  6.475  6.432  6.463 B1V                             
191854 20 08 33.7  43 47 43  9.982  9.274  8.864  9.134  8.539  8.433  7.671  7.641  6.813  6.817 G1     +                        
193901 20 20 38.8 -21 31 05 10.573 10.028  9.723  9.775  9.585  9.494  8.903  8.827  8.072  8.049 G3V                             
198188 20 46 21.9 -20 48 51 10.428  9.819  9.438  9.609  9.153  9.053  8.394  8.325  7.559  7.543 G0V                             
214680 22 37 00.7  38 47 22  4.268  4.349  4.381  4.716  4.834  4.858  4.811  4.880  4.898  4.921 B2                              
218687 23 07 27.5  14 09 22  8.793  8.211  7.846  7.984  7.586  7.475  6.821  6.760  6.003  5.976 G0V                             
219188 23 11 28.0  04 43 29  6.675  6.723  6.727  6.992  7.100  7.102  7.001  7.062  6.992  7.023 B0.5III*                        
__________________________________________________________________________________________________________                        
                                                                                                                                  
*  Primary flux standards (equatorial).                                                                                           
+  Primary solar analogs.                                                                                                         
                                                                                                                                  
                                                                                                                                  
Table VIII. Solar Analog Colors                                                                                                   
______________________________________________________________________                                                            
                                                                                                                                  
          Monochromatic Magnitude at Wavelength [A] Relative to 4845 A                                                            
  HD#    -------------------------------------------------------------                                                            
          3085   3365   3650   3871   4060   4260   5140   6840   7000                                                            
______________________________________________________________________                                                            
                                                                                                                                  
 28099   2.267  1.594  1.183  1.459   .863   .733  -.052  -.854  -.884                                                            
 29461   2.211  1.596  1.167  1.432   .854   .730  -.047  -.873  -.919                                                            
 30246   2.276  1.585  1.182  1.468   .871   .755  -.046         -.905                                                            
 44594   2.221  1.607  1.162  1.430   .837   .724  -.057  -.878  -.912                                                            
105590   2.224  1.586  1.155  1.452   .859   .749  -.052  -.893  -.925                                                            
186427   2.287  1.601  1.179  1.454   .858   .748  -.041  -.876  -.857                                                            
191854   2.311  1.603  1.193  1.463   .868   .762  -.030  -.858  -.854                                                            
                                                                                                                                  
  Mean   2.257  1.596  1.174  1.451   .859   .743  -.046  -.872  -.894                                                            
 Sigma    .038   .008   .013   .015   .011   .014   .009   .014   .029                                                            
________________________________________________________________________                                                          
                                                                                                                                  
                                                                                                                                  
C. Standards for Polarimetry                                                                                                      
                                                                                                                                  
        Both highly polarized stars (POL-STD in the FITS HISTORY keyword)                                                         
and unpolarized stars (UNPOL-STD in the FITS HISTORY keyword) were used to                                                        
calibrate the polarimetric measurements.  The standard values were taken                                                          
from the literature by the observers.  In some cases, the observers did not                                                       
provide us with information on which standard stars were used for the                                                             
calibration but the information is included under the HISTORY keyword                                                             
when the information is available.  References for standard values                                                                
were also not always provided.  One known reference was Hsu and Breger (1982).                                                    
                                                                                                                                  
                                                                                                                                  
V. REDUCTION OF NARROW-BAND PHOTOMETRY                                                                                            
                                                                                                                                  
	In this section are described the methods and formulae used at the                                                               
University of Maryland to reduce the narrow-band photometric data.  Most                                                          
data were reduced at Maryland, using these methods. Significant deviations                                                        
from these procedures are noted in the archive as comments for the relevant                                                       
observations.                                                                                                                     
                                                                                                                                  
A. Atmospheric Effects and Reduction to Standard Magnitudes                                                                       
                                                                                                                                  
	The most basic data with which we could begin reductions consisted                                                               
of Universal Times and counting rates on the various objects and on the                                                           
sky. In the case of measurements with direct-current systems rather than                                                          
pulse-counting systems, the most basic data would consist of readings                                                             
from the d.c. amplifier and Universal Times. Some observers submitted                                                             
data in various stages of reduction beyond these most basic data and                                                              
in general we do not know the details of the reductions applied by such                                                           
observers. We will describe here the complete reduction from the most                                                             
basic data as we carried it out.                                                                                                  
                                                                                                                                  
	Instrumental magnitudes were derived by first correcting all                                                                     
counting-rates for the dead-time of the amplifier using the formula                                                               
                                                                                                                                  
	n = n(obs)/[1.0 - n(obs)*tau]                                                                                                    
                                                                                                                                  
where tau is the dead-time of the amplifier and n and n(obs) are the                                                              
'true' and observed counting rates, respectively. These counting rates                                                            
were converted to instrumental magnitudes by choosing an appropriate                                                              
counting rate n(sky) for the sky brightness (by interpolation where                                                               
appropriate and possible) and using                                                                                               
                                                                                                                                  
	m = 20.00 - 2.5*log[n(object) - n(sky)].                                                                                         
                                                                                                                                  
	Air masses were calculated for each observation in the following                                                                 
manner beginning with the coordinates of the observatory and the coordinates                                                      
(current epoch) of the object.  True zenith distance, Z:                                                                          
                                                                                                                                  
	sec Z = 1/[sin(lat)*sin(dec) + cos(lat)*cos(dec)*cos(local hour angle)].                                                         
                                                                                                                                  
Apparent zenith distance, Zapp:                                                                                                   
                                                                                                                                  
	Zapp = Z - [60.4*tan(Z) - .06688*tan(Z)**3]                                                                                      
                                                                                                                                  
where the term in [ ] is in arcsec.  Airmass, X, is then:                                                                         
                                                                                                                                  
	X = sec(Zapp) - .0018167*[sec(Zapp)-1] - .002875*[sec(Zapp)-1]**2                                                                
	    - .0008083*[sec(Zapp)-1]**3.                                                                                                 
                                                                                                                                  
	Although atmospheric attenuation is normally linear with airmass as                                                              
defined above, this is not the case for observations with the OH filters                                                          
because the monochromatic attenuation varies drastically across the                                                               
bandpass. In order to simplify the reductions, particularly when only                                                             
limited data were available, the non-linearity of the atmospheric                                                                 
attenuation was modelled by defining an effective airmass, Xeff, such                                                             
that attenuation would be linear in this variable. Unfortunately, the                                                             
non-linearity varies from one site to another and even with time at a                                                             
single site due to differences in the amount of atmosphere above the                                                              
site (changing the Rayleigh component), in the amount of aerosol at the                                                           
site, and in the amount of ozone above the site. Furthermore, the                                                                 
non-linearity depends on the color of the source being observed.                                                                  
Fortunately we are interested only in sources of three colors -                                                                   
B-stars, solar analogs, and cometary emission bands. We can therefore                                                             
define effective airmasses separately for each of the three cases.                                                                
                                                                                                                                  
	The details of the atmospheric modelling will be described elsewhere                                                             
but our general approach, based on that of Hayes and Latham (1975), is to                                                         
use a three-component model for the atmosphere (Rayleigh, aerosol, ozone) to                                                      
calculate the monochromatic extinction. The altitude of the observatory                                                           
defines the Rayleigh component whereas the aerosol and ozone components are                                                       
allowed to vary within ranges expected for a given site. The monochromatic                                                        
extinction for various airmasses is then multiplied by the spectral                                                               
distribution of a B-star, a G-star, and a cometary emission band and the                                                          
resultant flux is multiplied by the transmission curve of the filter                                                              
yielding magnitudes as a function of airmass. The resultant theoretically                                                         
calculated magnitudes are compared with whatever observations are                                                                 
available, usually a large set of observations of the B-stars observed                                                            
over a wide range of airmasses during a single observing run. The two                                                             
free parameters (ozone column density and aerosol abundance) are varied                                                           
until the observed data are reproduced by the model. (Usually only the                                                            
ozone abundance needs to be varied significantly and it turns out that                                                            
in cases studied so far this remains within the ranges expected for a                                                             
given latitude and season.) We then use the calculated variation of                                                               
magnitude with airmass to define the effective airmass, Xeff, such that                                                           
the extinction is linear. It appears adequate to use a quadratic                                                                  
polynomial:                                                                                                                       
                                                                                                                                  
	Xeff = X + a*X**2                                                                                                                
                                                                                                                                  
where a is in principle different for every site (conceivably every                                                               
observing run due to seasonal effects in ozone abundance) and different                                                           
for B-stars, G-stars, and comets.                                                                                                 
                                                                                                                                  
	Since in practice one determines extinction only from B-stars or                                                                 
only from B- and G-stars, it is also necessary to know the ratio of                                                               
extinction coefficents for the three classes of objects once they have                                                            
all been linearized by the above formulae. This ratio is also derived                                                             
from the model.  Results from the models for a few observatories, as used                                                         
in our reductions, are given in Table IX, where the letters B, G, and C in                                                        
parentheses refer to the values of the parameters for B-stars, G-stars,                                                           
and Comets respectively.  More recent calculations lead to slightly different                                                     
values for the coefficients but the ones in the table are those that were                                                         
used for our reductions.  It can be seen that the curvature of the extinction                                                     
is larger at Mauna Kea than at the sites at lower altitudes.  It is also the                                                      
case that at these wavelengths the extinction at Mauna Kea is as large as it                                                      
is at good sites at lower altitudes.  This is presumably due to a greater                                                         
column of ozone over Mauna Kea at the time these measurements were taken                                                          
thanover the other sites at lower elevations.  Indeed, the model of the                                                           
extinction does require a greater column of ozone.                                                                                
                                                                                                                                  
                                                                                                                                  
Table IX. Coefficients for Extinction with the OH Filter                                                                          
________________________________________________________                                                                          
                                                                                                                                  
Parameter      Lowell     Mauna Kea  Cerro Tololo                                                                                 
________________________________________________________                                                                          
                                                                                                                                  
   a(B)        -0.0455     -0.0726     -0.0482                                                                                    
                                                                                                                                  
   a(G)        -0.0796     -0.1000     -0.0824                                                                                    
                                                                                                                                  
   a(C)        -0.00929    -0.0273     -0.00754                                                                                   
                                                                                                                                  
 k(G)/k(B)      0.973       0.930       0.973                                                                                     
                                                                                                                                  
 k(C)/k(B)      0.924       0.923       0.900                                                                                     
                                                                                                                                  
	Given a set of observations of standard stars, extinction                                                                        
coefficients were determined in a variety of ways. In most cases we                                                               
determined atmospheric extinction for each night by two methods, conventional                                                     
fitting by least squares of magnitude vs. airmass for individual stars                                                            
and also a global least squares solution using all standards in which we                                                          
solved simultaneously for the extinction coefficient and the zero-point                                                           
shift from instrumental magnitude to standard magnitudes. The result of                                                           
the global solution was normally used unless the solutions for individual                                                         
stars suggested hemispheric asymmetries and/or temporal variations                                                                
during the night. In these cases we then solved separately for different                                                          
hemispheres and/or parts of the night. In some cases we also averaged                                                             
several nights together to define average extinction coefficients either                                                          
when there were too few data on a particular night to determine                                                                   
extinction or when the scatter from night to night was no larger than                                                             
expected from the errors in the results of the individual nights.                                                                 
Different types of extinction fitting are noted in the remarks column of                                                          
the archive. When global solutions for extinction were not used,                                                                  
magnitudes were transformed to the standard system by a least squares                                                             
solution for the zero-point shift with no color terms.                                                                            
                                                                                                                                  
	It was at this point that a certain amount of discretion was exercised                                                           
in our operation. If individual observations or even all the observations of                                                      
a single object seemed discrepant, and if we were able to identify a                                                              
physically plausible mechanism for producing the discrepancy, we often                                                            
discarded those observations. In a few cases, we even discarded the data                                                          
from entire nights at this point. We should point out that in some cases                                                          
the observers had already advised us that the data were of poor quality                                                           
but we had requested that they submit everything in the hope that we                                                              
could salvage some marginal data if it turned out to be critical for                                                              
filling in a significant gap in the light curve. The subjective comments                                                          
of the observers were of great help in understanding the effects of                                                               
atmospheric extinction.                                                                                                           
                                                                                                                                  
B. Conversion to Fluxes                                                                                                           
                                                                                                                                  
	The following procedures were used to derive fluxes in the                                                                       
continuum bandpasses. These procedures are rather sensitive to the actual                                                         
shape of the bandpass of the filter since they involve integrating                                                                
the product of the filter transmission curve and the emission profile.                                                            
These steps are, therefore, the steps that will rapidly become incorrect                                                          
if the bandpass of a filter shifts with age.                                                                                      
        We first applied a correction due to the fact that the filter                                                             
at 4845A, nominally a continuum filter, also includes a weak tail of                                                              
emission from the delta-v = 0 sequence of the Swan system of C2 which                                                             
is measured by the filter at 5140A. This correction was done in magnitude                                                         
units using                                                                                                                       
                                                                                                                                  
	mcont(4845) = m(4845) + 0.012*[m(4845)-m(5140)].                                                                                 
                                                                                                                                  
The coefficient 0.012 was derived on the basis of theoretical spectra of                                                          
the Swan bands from A'Hearn (1978). Actual spectra of comet P/Halley from                                                         
Lowell Observatory suggest that the coefficient should be somewhat larger                                                         
than this, perhaps as large as 0.03. In any case, the correction does not                                                         
change the continuum flux drastically.                                                                                            
                                                                                                                                  
	The conversion from magnitudes in the standard system to fluxes in                                                               
the continuum is straightforward. To generalize for future use, we                                                                
arbitrarily define                                                                                                                
                                                                                                                                  
	mcont(6840) = m(6840)                                                                                                            
                                                                                                                                  
and                                                                                                                               
                                                                                                                                  
	mcont(3650) = m(3650).                                                                                                           
                                                                                                                                  
We also define                                                                                                                    
                                                                                                                                  
	Fcont(lambda) = 10**[-0.4 * mcont(lambda)]                                                                                       
                                                                                                                                  
The flux per unit wavelength [erg/cm**2/s/A] is then given by:                                                                    
                                                                                                                                  
	Flam(3650) = (8.22 +/- .13)*10**(-9) * Fcont(3650)                                                                               
	Flam(4845) = (5.10 +/- .30)*10**(-9) * Fcont(4845)                                                                               
	Flam(6840) = (1.65 +/- .02)*10**(-9) * Fcont(6840).                                                                              
                                                                                                                                  
The 'errors' given with the coefficients are a measure of the variation                                                           
in the flux transformation from one filter to another and, for a given                                                            
filter, with temperature over the range -20C to +20C.  These errors do not                                                        
include the uncertainties in the stellar spectra (some published, others from                                                     
unpublished material) that were used in the calibration.                                                                          
                                                                                                                                  
	Derivation of fluxes in emission bands is somewhat more complicated.                                                             
The first step is to remove the continuum which underlies the emission band                                                       
and which is also detected through the filters. This is done using the                                                            
colors of the solar analogs (Table VIII) and measurements of the comet                                                            
in any two continuum bandpasses - (3650,4845), (3650,6840), or                                                                    
(4845,6840). For each pair of filters, we interpolate (or extrapolate) the                                                        
magnitudes of the solar analogs to the wavelength of an emission-band                                                             
filter and determine the difference between the measured magnitude                                                                
and the interpolated magnitude, C. For the comet, we then interpolate the                                                         
magnitudes in the same two continuum filters and add C to estimate the                                                            
continuum contribution to the measured magnitude. This procedure is                                                               
accurate if the cometary continuum in magnitudes is redder (or bluer)                                                             
than the sun linearly with wavelength. If there is curvature or                                                                   
structure in the continuum reflectivity of the cometary grains, then                                                              
this procedure is not adequate. The general form of the equation is:                                                              
                                                                                                                                  
	mcont(i) = A*mcont(cont1) + (1-A)*mcont(cont2) + B(i)                                                                            
                                                                                                                                  
where i refers to the ith emission band designated by its wavelength,                                                             
A and (1-A) are the coefficients for the interpolation which depend only on                                                       
the wavelengths of the 3 filters, and B is as described above. In Table X                                                         
we give the coefficents for the continuum correction for each emission                                                            
band filter and for each of the three possible pairs of continuum bandpasses.                                                     
We also give an error in B which is a measure of the scatter from one solar                                                       
analog to another.                                                                                                                
                                                                                                                                  
                                                                                                                                  
Table X. Coefficients for Continuum Subtraction                                                                                   
________________________________________________                                                                                  
                                                                                                                                  
                         cont1/cont2                                                                                              
Filter      ------------------------------------                                                                                  
              3650/4845   4845/6840    3650/6840                                                                                  
________________________________________________                                                                                  
                                                                                                                                  
OH       A     1.4728      1.8822       1.1771                                                                                    
(3085)   B      .528       1.488         .721                                                                                     
      sigma(B)  .040        .037         .038                                                                                     
                                                                                                                                  
NH       A     1.2385      1.7419       1.0893                                                                                    
(3365)   B      .142        .949         .239                                                                                     
      sigma(B)  .018        .013         .015                                                                                     
                                                                                                                                  
CN       A      .8151      1.4882        .9307                                                                                    
(3871)   B      .494       1.025         .419                                                                                     
      sigma(B)  .018        .015         .018                                                                                     
                                                                                                                                  
C3       A      .6569      1.3935        .8715                                                                                    
(4060)   B      .088        .516        -.052                                                                                     
      sigma(B)  .014        .011         .015                                                                                     
                                                                                                                                  
CO+      A      .4895      1.2932        .8088                                                                                    
(4260)   B      .168        .487        -.040                                                                                     
      sigma(B)  .015        .014         .016                                                                                     
                                                                                                                                  
C2       A     -.2469       .8521        .5329                                                                                    
(5140)   B      .244        .083        -.264                                                                                     
      sigma(B)  .010        .008         .012                                                                                     
                                                                                                                                  
H2O+     A    -1.8033      -.0802       -.0502                                                                                    
(7000)   B     1.223        .048         .083                                                                                     
      sigma(B)  .037        .030         .030                                                                                     
________________________________________________                                                                                  
                                                                                                                                  
                                                                                                                                  
	In reducing the data we often had a choice of which continuum                                                                    
bandpasses to use for the continuum subtraction. We always chose inter-                                                           
polation over extrapolation and the shorter of the two possible baselines.                                                        
To define the fluxes in the emission bands, we first define:                                                                      
                                                                                                                                  
	F(i) = 10**[-0.4*m(i)]                                                                                                           
	Fcont(i) = 10**[-0.4*mcont(i)]                                                                                                   
                                                                                                                                  
where we will denote the individual emission bands, i, by their                                                                   
wavelengths [A]. The true fluxes in the emission bands [erg/cm**2/s]                                                              
are then given by:                                                                                                                
                                                                                                                                  
	F(OH) = (Y1 - 0.0015*T)*10**(-6) * [F(3085) - Fcont(3085)]                                                                       
	F(NH) = (Y2)*10**(-7) * [F(3365) - Fcont(3365)]                                                                                  
	F(CN) = (Y3 - .0021*T)*10**(-6) * [F(3870) - Fcont(3870)]                                                                        
	F(C3) = (1.381 + .003*T)*10**(-6) * [F(4060) - Fcont(4060)]                                                                      
	F(CO+) = (5.90 - .005*T)*10**(-7) * [F(4260) - Fcont(4260)]                                                                      
	F(C2) = 6.81*10**(-7) * [F(5140) - Fcont(5140)]                                                                                  
	F(H2O+) = 3.58*10**(-7) * [F(7000) - Fcont(7000)]                                                                                
                                                                                                                                  
where T is the temperature [deg C] of the filter. The coefficients Y1, Y2,                                                        
and Y3 must be tabulated. Y2 varies from one filter to another because                                                            
the filters for NH (which are not widely distributed) are much older                                                              
than the filters distributed by the IHW and they are not nearly as well                                                           
matched to each other. For filter #S1, Y2 = 8.079 + .0080*T; for filter #S2,                                                      
Y2 = 8.240 + .0095*T; for filter #S3, Y2 = 9.040 + .0150*T. The                                                                   
coefficients Y1 and Y3, on the other hand, vary with the comet's                                                                  
heliocentric radial velocity Vr because of the very large Swings effect on                                                        
the bands of OH and CN. These coefficients are tabulated in Table XI.                                                             
                                                                                                                                  
                                                                                                                                  
Table XI. Transformation Coefficients Y1 for OH and Y2 for CN                                                                     
____________________________________________________________________________                                                      
                                                                                                                                  
  Vr    Y1     Y3     Vr    Y1     Y3    Vr    Y1     Y3    Vr    Y1     Y3                                                       
[km/s]              [km/s]             [km/s]             [km/s]                                                                  
____________________________________________________________________________                                                      
                                                                                                                                  
 -60  1.080  .5277   -30  1.099  .5188    1         .5230   31         .5267                                                      
 -59         .5273   -29         .5214    2  1.189  .5238   32  1.100  .5270                                                      
 -58  1.086  .5276   -28  1.112  .5247    3         .5245   33         .5272                                                      
 -57         .5284   -27         .5272    4  1.161  .5251   34  1.117  .5271                                                      
 -56  1.093  .5304   -26  1.128  .5287    5         .5257   35         .5268                                                      
 -55         .5329   -25         .5289    6  1.147  .5263   36  1.136  .5263                                                      
 -54  1.101  .5358   -24  1.132  .5288    7         .5267   37         .5258                                                      
 -53         .5378   -23         .5286    8  1.151  .5274   38  1.134  .5255                                                      
 -52  1.106  .5380   -22  1.119  .5280    9         .5282   39         .5254                                                      
 -51         .5362   -21         .5268   10  1.140  .5289   40  1.118  .5258                                                      
 -50  1.111  .5333   -20  1.105  .5248   11         .5291   41         .5261                                                      
 -49         .5306   -19         .5229   12  1.113  .5288   42  1.094  .5263                                                      
 -48  1.128  .5285   -18  1.112  .5214   13         .5285   43         .5265                                                      
 -47         .5273   -17         .5210   14  1.092  .5289   44  1.069  .5267                                                      
 -46  1.156  .5269   -16  1.121  .5214   15         .5214   45         .5269                                                      
 -45         .5270   -15         .5223   16  1.087  .5290   46  1.057  .5274                                                      
 -44  1.170  .5277   -14  1.108  .5234   17         .5275   47         .5277                                                      
 -43         .5287   -13         .5244   18  1.095  .5275   48  1.052  .5275                                                      
 -42  1.146  .5300   -12  1.111  .5261   19         .5290   49         .5277                                                      
 -41         .5309   -11         .5292   20  1.090  .5307   50  1.050  .5286                                                      
 -40  1.126  .5307   -10  1.154  .5336   21         .5312   51         .5304                                                      
 -39         .5299   - 9         .5372   22  1.074  .5309   52  1.052  .5320                                                      
 -38  1.120  .5287   - 8  1.235  .5395   23         .5307   53         .5327                                                      
 -37         .5275   - 7         .5402   24  1.059  .5309   54  1.057  .5323                                                      
 -36  1.108  .5263   - 6  1.236  .5394   25         .5310   55         .5312                                                      
 -35         .5250   - 5         .5371   26  1.054  .5305   56  1.061  .5296                                                      
 -34  1.089  .5232   - 4  1.215  .5332   27         .5292   57         .5282                                                      
 -33         .5208   - 3         .5290   28  1.061  .5277   58  1.064  .5269                                                      
 -32  1.088  .5186   - 2  1.202  .5256   29         .5267   59         .5256                                                      
 -31         .5179   - 1         .5236   30  1.078  .5266   60  1.067  .5243                                                      
                       0  1.208  .5228                                                                                            
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
C. Errors                                                                                                                         
                                                                                                                                  
	Errors were not always treated consistently. For the polarimetry                                                                 
we simply used the errors provided by the observers, who had been asked to                                                        
supply the standard deviation of the final answer, both for the percent                                                           
polarization and for the position angle.                                                                                          
                                                                                                                                  
	For the narrow-band photometry, we normally calculated the errors                                                                
ourselves by propagating the errors through each step of the reduction.                                                           
In some cases, however, we did not know the uncertainties, e.g., in the                                                           
raw count rates, and we had to guess these errors. Wherever possible, we                                                          
checked the scatter among different measurements to ensure that this was                                                          
consistent with the expected error in an individual measurement. If they                                                          
were not consistent, we always chose the larger error. This typically                                                             
occurred when we derived the zero-point shift to the standard magnitude                                                           
system. The scatter in zero-point shift from one standard star to                                                                 
another was often greater than one would expect from the uncertainties                                                            
in the raw counting rates and in the extinction determinations. The                                                               
resultant errors, when propagated through to the fluxes, represent only                                                           
the photometric uncertainty. They do not include uncertainties in the                                                             
transformation equations given above nor do they include uncertainties                                                            
due to the scatter in characteristics among the different filters nor do                                                          
they include the errors in the flux-calibrated spectra of the standard                                                            
stars that were used to derive the transformation coefficients.                                                                   
                                                                                                                                  
	We do know that we have neglected one significant source of error.                                                               
As noted above, our algorithm for removing the continuum from the                                                                 
measurements of emission bands will only work if the reddening (in                                                                
magnitudes) is linear with wavelength. Empirically we have found that                                                             
frequently the flux of CO+ turns out to be negative. We have looked into                                                          
the contamination of the continuum bandpasses by emission bands and have                                                          
concluded that this is not the source of the problem. We suspect that                                                             
the real problem is due to non-linearity in the reddening of the solar                                                            
continuum by the cometary grains but we have no way of adequately                                                                 
dealing with this. The effect is most pronouced for CO+ because the band                                                          
is very weak compared to the continuum near the nucleus but the problem                                                           
is presumably present, to a lesser degree, for all emission bands.                                                                
                                                                                                                                  
	Other than the uncertainty due to the varying reflectivity of                                                                    
cometary grains, we believe that the photometric uncertainty is the largest                                                       
uncertainty in the results presented here and that the quoted errors are                                                          
reasonably realistic. We note that although the CO+ feature is                                                                    
frequently negative, it is virtually never more than 3-sigma negative.                                                            
In the data tables, our general policy has been to quote 1-sigma                                                                  
errors. If the result is less than 3-sigma, we have usually quoted a                                                              
3-sigma upper limit but in a few cases we have included results between                                                           
2- and 3-sigma together with the errors.                                                                                          
                                                                                                                                  
                                                                                                                                  
VI. CONTENT OF THE ARCHIVE                                                                                                        
                                                                                                                                  
A. The Data                                                                                                                       
                                                                                                                                  
     In order to provide an overview of the archive content, Table XII offers                                                     
a chronological summary of the data.  Listed are the calendar month and the                                                       
number of observations archived for each of three different types -                                                               
magnitudes, fluxes, and polarizations.  Note that several sets of data                                                            
taken with the narrow-band filters were archived as magnitudes rather                                                             
than fluxes because we thought that conversion to fluxes either was too                                                           
uncertain or would involve only a small subset of the data.  If these                                                             
narrow-band data were thought to be useful in the form of magnitudes,                                                             
either because they formed useful maps or formed useful time-series, we                                                           
archived them in that form.  Note also that the polarimetric measurements                                                         
came in two forms, although they are combined in Table XII.                                                                       
                                                                                                                                  
     The data were taken by 116 different observers using 53 different                                                            
instruments.  The observers are listed in Table XIII, together with their                                                         
affiliation.  In some cases we have given the observer's affiliation as                                                           
his or her home institution and in other cases as the observatory at which                                                        
he or she observed, depending on the information available to us.  An                                                             
examination of Table XIII shows that the observers came from 16 different                                                         
countries (additoinal countries were also represented in the data we were                                                         
unable to archive).  An examination of the observing sites shows data                                                             
from observatories in at least 14 countries which only partially overlap                                                          
the set of countries in which the observers were based.                                                                           
                                                                                                                                  
                                                                                                                                  
Table XII. Chronological Listing of the Data                                                                                      
____________________________________________________________________________                                                      
                                                                                                                                  
Date UT          Number of Observations                                                                                           
Year/Mon     Magnitudes   Fluxes   Polarizations                                                                                  
____________________________________________________________________________                                                      
                                                                                                                                  
1981 Dec          3(limits)  -          -                                                                                         
1982 Oct          4          -          -                                                                                         
1982 Nov          2          -          -                                                                                         
1982 Dec          2          -          -                                                                                         
1983 Jan          1          -          -                                                                                         
1983 Feb          2          -          -                                                                                         
1984 Jan         36          -          -                                                                                         
1984 Feb          9          -          -                                                                                         
1984 Mar          1          -          -                                                                                         
1984 Oct         13          -          -                                                                                         
1984 Nov         14          -          -                                                                                         
1984 Dec         73          -          -                                                                                         
1985 Jan         30          -          -                                                                                         
1985 Feb         14          -          -                                                                                         
1985 Mar         16          -          -                                                                                         
1985 Apr          4          -          -                                                                                         
1985 Aug         31          8          -                                                                                         
1985 Sep        217        440         14                                                                                         
1985 Oct        149        235         58                                                                                         
1985 Nov        340       1948        178                                                                                         
1985 Dec        175        941        195                                                                                         
1986 Jan         24        363         60                                                                                         
1986 Feb          -         27          1                                                                                         
1986 Mar        132       1671         76                                                                                         
1986 Apr         53       7094        188                                                                                         
1986 May         53       2921        114                                                                                         
1986 Jun         43        404          -                                                                                         
1986 Jul         14         32          -                                                                                         
1987 Jan          8         21          -                                                                                         
1987 Feb          4          -          -                                                                                         
1987 Mar        255         51          -                                                                                         
1988 Apr         27          -          -                                                                                         
1988 May         26          -          -                                                                                         
                                                                                                                                  
Total interval - 7 years 5 months; total number of observations - 1775 magni-                                                     
tudes, 16,156 fluxes, and 884 polarizations.                                                                                      
                                                                                                                                  
                                                                                                                                  
                                                                                                                                  
Table XIII. List of Observers and Their Affiliations                                                                              
________________________________________________________________________________                                                  
                                                                                                                                  
Observer             Affiliation                                                                                                  
________________________________________________________________________________                                                  
                                                                                                                                  
M.F. A'Hearn         University of Maryland, U.S.A.                                                                               
E. Alvarez           Kitt Peak National Observatory, U.S.A.                                                                       
P.J. Andrews         Royal Greenwich Observatory, U.K.                                                                            
J. Arnaud            Observatoires du Pic du Midi et de Toulouse, France                                                          
E.S. Barker          McDonald Observatory, U.S.A.                                                                                 
G.A. Baratta         Citta Universitaria - Catania, Italy                                                                         
P. Bastien           Universite de Montreal, Canada                                                                               
J. Baudrand          Observatoire de Paris - Meudon, France                                                                       
M.J.S. Belton        Kitt Peak National Observatory, U.S.A.                                                                       
P.V. Birch           Perth Observatory, Australia                                                                                 
N. Brosch            Wise Observatory, Israel                                                                                     
H. Butcher           Kitt Peak National Observatory, U.S.A.                                                                       
F.A. Catalano        Citta Universitaria - Catania, Italy                                                                         
G.P. Chernova        Institute of Astrophysics - Dushanbe, U.S.S.R.                                                               
A. Chevillot         Observatoire de Paris - Meudon, France                                                                       
K.I. Churyumov       T. G. Shevchenko Kiev University, U.S.S.R.                                                                   
J.J. Claria          Observatorio Astronomico - Cordoba, Argentina                                                                
M. Combes            Observatoire de Paris - Meudon, France                                                                       
D. Cruissaire        Observatoire de Paris - Meudon, France                                                                       
G.E. Danielson       California Institute of Technology & JPL, U.S.A.                                                             
A. Dollfus           Observatoire de Paris, France                                                                                
L. Drissen           Universite de Montreal, Canada                                                                               
Y.S. Efimov          Crimean Astrophysical Observatory, U.S.S.R.                                                                  
M.A. Eritzian        Byurakan Astrophysical Observatory, U.S.S.R.                                                                 
P. Felenbok          Observatoire de Paris - Meudon, France                                                                       
A. Fitzsimmons       University of Leicester, U.K.                                                                                
E. Gerard            Observatoire de Paris - Meudon, France                                                                       
S.I. Gerasimenko     Institute of Astrophysics - Dushanbe, U.S.S.R.                                                               
S.Y. Gorda           Kourovskaya Observatory, U.S.S.R.                                                                            
J. Guerin            Observatoire de Paris - Meudon, France                                                                       
H.H. Guetter         U. S. Naval Observatory - Flagstaff, U.S.A.                                                                  
A.L. Guralchuk       Tarija expedition, U.S.S.R.                                                                                  
H.B. Hammel          University of Hawaii, U.S.A.                                                                                 
D. Jewitt            California Institute of Technology & MIT, U.S.A.                                                             
A. John              Perth Observatory, Australia                                                                                 
J. Johnston          Perth Observatory, Australia                                                                                 
H.E. Jorgensen       University Observatory - Copenhagen, Denmark                                                                 
V.V. Kayumov         Institute of Astrophysics - Dushanbe, U.S.S.R.                                                               
S. Kikuchi           Tokyo Astronomical Observatory, Japan                                                                        
G.C. Kilambi         Osmania University - Hyderabad, India                                                                        
R. Killinger         Ruhr Universitaet - Bochum, FRG                                                                              
N.N. Kiselev         Institute of Astrophysics - Dushanbe, U.S.S.R.                                                               
P. Kjaergaard        University Observatory - Copenhagen, Denmark                                                                 
P.P. Korsun          Main Astronomical Observatory - Kiev, U.S.S.R.                                                               
V.P. Kozhevnikov     Kourovskaya Observatory, U.S.S.R.                                                                            
A.V. Krivtsov        Assy Observatory, U.S.S.R.                                                                                   
K.S. Kuratov         Assy Observatory, U.S.S.R.                                                                                   
E. Lapasset          Observatorio Astronomico - Cordoba, Argentina                                                                
N. Lark              University of the Pacific, U.S.A.                                                                            
J.F. Le Borgne       Observatoires du Pic du Midi et de Toulouse, France                                                          
J. Lecacheux         Observatoire de Paris-Meudon, France                                                                         
E.M. Leibowitz       Tel-Aviv University, Israel                                                                                  
G. Lelievre          Canada-France-Hawaii Telescope, U.S.A.                                                                       
J.P. Lemonnier       Canada-France-Hawaii Telescope, U.S.A.                                                                       
J.L. Leroy           Observatoires du Pic du Midi et de Toulouse, France                                                          
A.V. Loktin          Ural State University, U.S.S.R.                                                                              
D.F. Lupishko        Astronomical Observatory - Kharkov, U.S.S.R.                                                                 
J. Manfroid          Universite de Liege, Belgium                                                                                 
L. Martin            Lowell Observatory, U.S.A.                                                                                   
R. Martin            Perth Observatory, U.S.A.                                                                                    
P. McCarthy          University of California - Berkeley, U.S.A.                                                                  
K.J. Meech           MIT & University of Hawaii, U.S.A.                                                                           
F. Menard            Universite de Montreal, Canada                                                                               
Y. Mikami            Tokyo Astronomical Observatory, Japan                                                                        
R.L. Millis          Lowell Observatory, U.S.A.                                                                                   
A.S. Miroschnichenko Main Astronomical Observatory - Pulkovo, U.S.S.R.                                                            
H. Moreno            Universidad de Chile, Chile                                                                                  
A.V. Morozhenko      Main Astronomical Observatory - Kiev, U.S.S.R.                                                               
D.B. Mukanov         Assy Observatory, U.S.S.R.                                                                                   
R. Nadeau            Universite de Montreal, Canada                                                                               
I.V. Nosov           Astrophysics Institute - Kazakhstan, U.S.S.R.                                                                
C.B. Opal            McDonald Observatory, U.S.A.                                                                                 
H. Pedersen          European Southern Observatory, Chile                                                                         
W. Pfau              Friedrich-Schiller-Universitat, GDR                                                                          
J.P. Picat           Observatoire du Pic du Midi, France                                                                          
D.J. Piscitelli      University of Hawaii, U.S.A.                                                                                 
J.I. Polevaya        Institute of Astrophysics - Dushanbe, U.S.S.R.                                                               
T.S. Polyshina       Ural State University, U.S.S.R.                                                                              
C.L. Presti          Citta Universitaria - Catania, Italy                                                                         
V.Y. Rakhimov        Institute of Astrophysics - Dushanbe, U.S.S.R.                                                               
G.R. Ricker          MIT, U.S.A.                                                                                                  
D.I. Rodetsky        Assy Observatory, U.S.S.R.                                                                                   
K.I. Rspayev         T. G. Shevchenko Kiev University, U.S.S.R.                                                                   
N. St.Louis          Universite de Montreal, Canada                                                                               
M.B. K. Sarma        Osmania University - Hyderabad, India                                                                        
D.G. Schleicher      Lowell Observatory,U.S.A.                                                                                    
N.M. Shakhovskoy     Crimean Astrophysical Observatory, U.S.S.R.                                                                  
V.G. Shevchenko      Institut Kosmicheskiikh Issledovaniikh, U.S.S.R.                                                             
T. Siklitsky         Institute of Astrophysics - Dushanbe, U.S.S.R.                                                               
R.F. Sistero         Observatorio Astronomico - Cordoba, Argentina                                                                
H. Spinrad           University of California-Berkeley, U.S.A.                                                                    
B. Stecklum          Friedrich-Schiller-Universitat, GDR                                                                          
C. Sterken           Vrije Universiteit,Brussels, Belgium                                                                         
R.P. S. Stone        Lick Observatory, U.S.A.                                                                                     
A. D. Storrs         University of Hawaii, U.S.A.                                                                                 
G. Strazzulla        Citta Universitaria - Catania, Italy                                                                         
J.L. Suchail         Ecole Normale Superieure - Paris, France                                                                     
K.V. Tarasov         Institute of Astrophysics - Dushanbe, U.S.S.R.                                                               
D.J. Tholen          University of Hawaii,U.S.A.                                                                                  
D.T. Thompson        Lowell Observatory,U.S.A.                                                                                    
L.I. Tsvetkov        Institute of Astrophysics - Dushanbe, U.S.S.R.                                                               
F.A. Tupieva         Institute of Astrophysics - Dushanbe, U.S.S.R.                                                               
R.A. Vardanian       Byurakan Astrophysical Observatory, U.S.S.R.                                                                 
F.P. Velichko        Astronomical Observatory - Kharkov, U.S.S.R.                                                                 
P. Vivekananda Rao   Osmania University - Hyderabad, India                                                                        
F.J. Vrba            U. S. Naval Observatory - Flagstaff, U.S.A.                                                                  
R.L. Walker          U. S. Naval Observatory - Flagstaff, U.S.A.                                                                  
L. Walsh             Perth Observatory, Australia                                                                                 
P.A. Wehinger        Arizona State University, U.S.A.                                                                             
E. Wenderoth         Universidad de Chile, Chile                                                                                  
R.M. West            European Southern Observatory, FRG                                                                           
I.P. Williams        Queen Mary College, U.K.                                                                                     
W. Wisniewski        University of Arizona, U.S.A.                                                                                
S. Wyckoff           Arizona State University, U.S.A.                                                                             
R.V. Yudin           Main Astronomical Observatory - Pulkovo, U.S.S.R.                                                            
N.Y. Yutanov         Main Astronomical Observatory - Pulkovo, U.S.S.R.                                                            
                                                                                                                                  
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
B. The FITS Files (Digital Archive)                                                                                               
                                                                                                                                  
     The data from the Photometry and Polarimetry Network are stored using                                                        
the Tables Extension of FITS ('EXTEND  =                    T'). Some of the                                                      
important parameters of the data are given in the standard FITS header while                                                      
the remainder are given in the tables. Regardless of the type of data, the                                                        
information in the FITS header is the same. The logically grouped content of                                                      
the various keywords in the header is given in Table XIV. Note that some                                                          
values, particularly 'TIME-OBS', have been truncated to the number of digits                                                      
meaningful for all entries in the file since the times of each individual                                                         
observation are given on each line of the actual tables of data.  FUrthermore,                                                    
the accuracy of the entries varies, particularly for the coordinates of the                                                       
observatory, since the coordinates were obtained from a variety of sources,                                                       
often the observers themselves.                                                                                                   
                                                                                                                                  
                                                                                                                                  
Table XIV. FITS Header Keywords                                                                                                   
________________________________________________________________________________                                                  
                                                                                                                                  
  Item         FITS Keyword  Format       Value/Explanation                                                                       
________________________________________________________________________________                                                  
                                                                                                                                  
Comet Name      OBJECT       string       'P/HALLEY' for all                                                                      
                                            files in this archive.                                                                
File Number     FILE-NUM     I6           '56xxxx'                                                                                
                                            5 ==> Photometry/Polarimetry                                                          
                                                  Network                                                                         
                                            6 ==> P/Halley                                                                        
                                            xxxx = running number, not in                                                         
                                                  chronological order                                                             
Date            DATE-OBS     dd/mm/yy     Date of the observations                                                                
UT Time         TIME-OBS     F6.5         Decimal fraction of the day at the                                                      
                                            midpoint of the observations in                                                       
                                            the table                                                                             
Our Network     DISCIPLN     string       'PHOTOMETRY' for this Network                                                           
Observatory     OBSVTORY     string       Name of observatory                                                                     
   Longitude    LONG-OBS     ddd/mm/ss    Positive, eastward from Greenwich                                                       
   Latitude     LAT--OBS     sdd/mm/ss    s='+' or '-' for North or South                                                         
   Elevation    ELEV-OBS     I4           [m]                                                                                     
   System       SYSTEM       I8           See Section VII.                                                                        
   Telescope    TELESCOP     string       A unique identification of the                                                          
                                            telescope by name or size                                                             
Type of data    DAT-TYPE     string       'POLARIMETRY', 'STOKES", 'BROADBAND',                                                   
                                            or 'NARROWBAND'. Note that in                                                         
                                            Table XI 'Fluxes' refers to                                                           
                                            'NARROWBAND' and 'Magnitudes'                                                         
                                            refers to 'BROADBAND'                                                                 
Observer(s)     OBSERVER     string       Name(s) of observer(s) (omitted for                                                     
                                            FES observations with IUE;large                                                       
                                            team headed by Feldman & Festou)                                                      
Submitter       SUBMITTR     string       Person who submitted data to the                                                        
                                            DS.  A blank usually means data                                                       
                                            were taken from the literature.                                                       
Comments        COMMENT      string       All comments are character strings                                                      
                                          (line = 80 characters) following the                                                    
                                          keywords 'COMMENT' and 'HISTORY'                                                        
                                          and in some cases the following                                                         
                                          secondary keywords:                                                                     
                                          'LIT.' => reference from literature                                                     
                                          'NOTE' => footnote to table                                                             
                                          'NOTExx' => footnote to line xx                                                         
                                          'ADD. OBS.' => names of additional                                                      
                                            observers beyond those above                                                          
                HISTORY      string       Comments relevant to calibration                                                        
                                            'STDSTARS' => list of standard stars                                                  
                                            used in the reduction. In case of                                                     
                                            polarimetry standard stars POL-STD                                                    
                                            refers to highly polarized stars,                                                     
                                            and UNPOL-STD to unpolarized stars.                                                   
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
     The FITS tables can take any of four different formats depending on                                                          
the type of data in the table.  The types of table are known by the                                                               
following values for the FITS 'DAT-TYPE' keyword: 'BROADBAND', 'NARROWBAND',                                                      
'POLARIMETRY', and 'STOKES'.  Note that the value 'BROADBAND' is actually                                                         
used to indicate results given in magnitudes rather than fluxes.  It is                                                           
independent of the actual bandwidth of the filters used.  The first few                                                           
columns in the tables are identical for all types of data and are listed in                                                       
Table XV.  The additional entries for DAT-TYPE = 'BROADBAND' are in Table XVI,                                                    
for DAT-TYPE = 'NARROWBAND' in Table XVII, for DAT-TYPE = 'POLARIMETRY' in                                                        
Table XVIII, and for DAT-TYPE= 'STOKES' in Table XIX.  The format of the                                                          
printed archive and the index table are described in Table XX.                                                                    
                                                                                                                                  
                                                                                                                                  
Table XV.  Columns Common to All Types of Data                                                                                    
_______________________________________________________________________________                                                   
                                                                                                                                  
Item                 Format    Columns        Explanation                                                                         
_______________________________________________________________________________                                                   
                                                                                                                                  
Date and time(UT)     F8.5      1 -   8       Day of month and decimal fraction                                                   
                                                at mid-point of observation                                                       
Serial number         I2       10 -  11       Line number in the table                                                            
                                                Occasional numbers are skipped                                                    
Filter name           A4       13 -  16       Short-hand name                                                                     
       wavelength     I4       18 -  21       Central wavelength [A]                                                              
       width          I4       23 -  26       FWHM [A]                                                                            
_______________________________________________________________________________                                                   
                                                                                                                                  
                                                                                                                                  
Table XVI.  Columns for Magnitudes (DAT-TYPE = 'BROADBAND')                                                                       
________________________________________________________________________________                                                  
                                                                                                                                  
Item                 Format    Columns        Explanation                                                                         
________________________________________________________________________________                                                  
                                                                                                                                  
Upper limit code      char        28          '<' indicates that the result in                                                    
                                                the following field is a                                                          
                                                3-sigma limit                                                                     
Magnitude             F7.3     30 -  36       Reduced magnitude                                                                   
       error          F5.3     38 -  42       One (1) sigma [mag];                                                                
                                                omitted if previous field is a                                                    
                                                limit                                                                             
Aperture size         F5.1     44 -  48       Diameter [arcsec]                                                                   
Radial offset         I4       50 -  53       Radial distance between center of                                                   
                                                aperture and the peak brightness                                                  
                                                of the comet [arcsec]                                                             
Offset direction      I3       55 -  57       Angular direction [deg]                                                             
                                                (eastward from north)                                                             
                                                of the radius vector to the                                                       
                                                center of the aperture from the                                                   
                                                peak in brightness                                                                
Integration time      I4       59 -  62       Integration time [s]                                                                
Airmass               F5.3     64 -  68       Airmass at midpoint in time,                                                        
                                                usually as quoted by observer                                                     
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
Table XVII.  Columns for Fluxes in Narrowband Filters (DAT-TYPE = 'NARROWBAND')                                                   
________________________________________________________________________________                                                  
                                                                                                                                  
Item                 Format    Columns        Explanation                                                                         
________________________________________________________________________________                                                  
                                                                                                                                  
Upper limit code      char        28          '<' indicates that the result in                                                    
                                                the following field is a                                                          
                                                3-sigma limit                                                                     
Log Flux              F7.3     30 -  36       Logarithm (base 10) of the flux                                                     
                                                See Section IV for details                                                        
        error         F5.3     38 -  42       Error of log10 of flux                                                              
Aperture size         F5.1     44 -  48       Diameter [arcsec]                                                                   
Radial offset         I4       50 -  53       Radial distance between center of                                                   
                                                aperture and the peak brightness                                                  
                                                of the comet [arcsec]                                                             
Offset direction      I3       55 -  57       Angular direction [deg]                                                             
                                                (eastward from north)                                                             
                                                of the radius vector to the                                                       
                                                center of the aperture from the                                                   
                                                peak in brightness                                                                
Integration time      I4       59 -  62       Integration time [s]                                                                
Airmass               F5.3     64 -  68       Airmass at midpoint in time                                                         
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
Table XVIII. Columns for Polarimetry in Percent (DAT-TYPE = 'POLARIMETRY')                                                        
________________________________________________________________________________                                                  
                                                                                                                                  
Item                 Format    Columns        Explanation                                                                         
________________________________________________________________________________                                                  
                                                                                                                                  
Polarization type     A2       28 -  29       'CR' => right circular                                                              
                                              'CL' => left circular                                                               
                                              'LN' => linear                                                                      
Polarization value    F5.2     31 -  35       Degree of polarization [%]                                                          
         error        F5.2     37 -  41       One (1) sigma [%]                                                                   
Position angle        F5.1     43 -  47       For linear polarization, the                                                        
                                                position angle of the electric                                                    
                                                vector [deg] clockwise from                                                       
                                                the plane of scattering                                                           
                                                (-45 to +135)                                                                     
         error        F4.1     49 -  52       One sigma                                                                           
Aperture size         F5.1     54 -  58       Diameter [arcsec]                                                                   
Radial offset         I4       60 -  63       Radial distance between center of                                                   
                                                aperture and the peak brightness                                                  
                                                of the comet [arcsec]                                                             
Offset direction      I3       65 -  67       Angular direction [deg]                                                             
                                                (eastward from north)                                                             
                                                of the radius vector to the                                                       
                                                center of the aperture from the                                                   
                                                peak in brightness                                                                
Integration time      I4       69 -  72       Integration time [s]                                                                
Airmass               F5.3     74 -  78       Airmass at midpoint in time,                                                        
                                                usually as quoted by observer                                                     
________________________________________________________________________________                                                  
                                                                                                                                  
                                                                                                                                  
Table XIX. Columns for Stokes Vectors (DAT-TYPE = 'STOKES')                                                                       
--------------------------------------------------------------------------------                                                  
                                                                                                                                  
Item                 Format    Columns        Explanation                                                                         
________________________________________________________________________________                                                  
                                                                                                                                  
Q/I                   F7.4     28 -  34       Normalized Stokes parameter Q/I,                                                    
                                                positive for the electric vector                                                  
                                                perpendicular to the plane of                                                     
                                                scattering, negative for the                                                      
                                                electric vector parallel to the                                                   
                                                plane [dimensionless]                                                             
         error        F6.4     36 -  41       One sigma                                                                           
U/I                   F7.4     43 -  49       Normalized Stokes parameter U/I,                                                    
                                                positive for the electric vector                                                  
                                                45 degrees counterclockwise                                                       
                                                from positive values of Q,                                                        
                                                negative for 45 degrees                                                           
                                                clockwise [dimensionless]                                                         
         error        F6.4     51 -  56       One sigma                                                                           
V/I                   F7.4     58 -  64       Normalized Stokes parameter V/I,                                                    
                                                positive for left handed as seen                                                  
                                                by the observer, negative for                                                     
                                                right handed as seen by the                                                       
                                                observer [dimensionless]                                                          
         error        F6.4     66 -  71       One sigma                                                                           
Aperture size         F5.1     73 -  77       Diameter [arcsec]                                                                   
Radial offset         I4       79 -  82       Radial distance between center of                                                   
                                                aperture and the peak brightness                                                  
                                                of the comet [arcsec]                                                             
Offset direction      I3       84 -  86       Angular direction [deg]                                                             
                                                (eastward from north)                                                             
                                                of the radius vector to the                                                       
                                                center of the aperture from the                                                   
                                                peak in brightness                                                                
Integration time      I4       88 -  91       Integration time [s]                                                                
Airmass               F5.3     93 -  97       Airmass at midpoint in time,                                                        
                                                usually as quoted by observer                                                     
--------------------------------------------------------------------------------                                                  
                                                                                                                                  
                                                                                                                                  
                                                                                                                                  
Table XX.  Format of the Printed Archive and the Index Table                                                                      
________________________________________________________________________________                                                  
                                                                                                                                  
Header        Value/Explanation                                                                                                   
________________________________________________________________________________                                                  
                                                                                                                                  
      GENERAL SECTION                                                                                                             
                                                                                                                                  
Date(UT)      Date of the middle of observation (in UT day and fraction)                                                          
PPN#          Photometry & Polarimetry Network number--a unique number for                                                        
                each FITS file                                                                                                    
Filter        Filter name                                                                                                         
Lambda        Central wavelength of filter [A]                                                                                    
Delta lambda  FWHM of filter [A]                                                                                                  
ApDia         Aperture diameter [arcsec]                                                                                          
ExpS          Integration time [s]                                                                                                
                                                                                                                                  
      FLUXES (NARROW-BAND PHOTOMETRY)                                                                                             
                                                                                                                                  
LogFlux       Logarithm (base 10) of the flux and uncertainty; '<' indicates                                                      
                a limit                                                                                                           
                                                                                                                                  
      POLARIMETRY                                                                                                                 
                                                                                                                                  
Type          Polarization type, 'CL' => left circular, 'CR' => right circular,                                                   
                'LN' => linear.                                                                                                   
Polar         Degree of polarization [%] and uncertainty (one sigma)                                                              
Angle         For linear polarization, the position angle of the electric vector                                                  
                [deg] clockwise from the plane of scattering and uncertainty                                                      
                                                                                                                                  
      MAGNITUDES (BROAD-BAND AND NARROW-BAND PHOTOMETRY)                                                                          
                                                                                                                                  
Mag           Magnitude in a photometric system and uncertainty; '<' indicates                                                    
                a 3-sigma limit                                                                                                   
                                                                                                                                  
      STOKES (POLARIMETRY)                                                                                                        
                                                                                                                                  
Q/I           Normalized Stokes parameter normal to scattering plane and                                                          
                uncertainty (one sigma); '<' indicates a 3-sigma limit                                                            
U/I           Normalized Stokes parameter at 45 degrees to scattering plane and                                                   
                uncertainty (one sigma); '<' indicates a 3-sigma limit                                                            
V/I           Normalized Stokes parameter for circular polarization and                                                           
                uncertainty (one sigma); '<' indicates a 3-sigma limit                                                            
                                                                                                                                  
      GENERAL SECTION (CONT.)                                                                                                     
                                                                                                                                  
Offset rho    Radial distance between center of aperture and the peak brightness                                                  
                of the comet [arcsec]                                                                                             
Offset theta  Angular direction [deg] (eastward from north) of the radius                                                         
                vector between the peak brightness and the center of the                                                          
                aperture.                                                                                                         
Airm          Airmass at mid-point of observation.                                                                                
System        System codes '5oooxxyy', See Section VII.                                                                           
Observer      Name(s) of observer(s)                                                                                              
Notes         Comment notes                                                                                                       
________________________________________________________________________________                                                  
                                                                                                                                  
VII. SYSTEM CODES                                                                                                                 
                                                                                                                                  
        The observers in our net used a wide variety of instruments and,                                                          
not surprisingly, provided us with a wide variety of information.  The                                                            
system codes in the FITS headers are meant to uniquely identify specific                                                          
telescope-instrument combinations.  The general structure used in                                                                 
constructing the codes is as follows:                                                                                             
1st digit = 5 (indicating this net)                                                                                               
digits 2-4 = an observatory code, normally from the IAU list of observatory                                                       
       codes but see the complete list of codes given in another appendix.                                                        
digits 5-6 = a telescope code, normally a sequential number in order of                                                           
       decreasing telescope size at a given site.                                                                                 
digits 7-8 = a unique number indicating (when used in conjunction with the                                                        
        previous digits) the equipment used.  Normally we                                                                         
        have used 1 to indicate photoelectric photometers, 2 to indicate                                                          
        ccds, and 6 to indicate polarimeters.  Where different instruments                                                        
        of the same type were used on a particular telescope, other numbers                                                       
        could be used.                                                                                                            
                                                                                                                                  
        Details of particular instruments, to the extent they are known                                                           
to us, are given in Table XXI.  Under comments we have also given the format                                                      
in which we received the data in some cases to indicate, e.g., that the                                                           
observer might have already taken into account the deadtime of a                                                                  
photomultiplier so that we did not need that information.  We have also                                                           
given the approxiamte number of FITS files based on the use of each                                                               
instrument, although the exact number may be slightly different due to                                                            
editing in the last stages of preparing the archive.                                                                              
                                                                                                                                  
                                                                                                                                  
Table XXI. System Codes                                                                                                           
--------------------------------------------------------------------------------                                                  
  code  Observatory  # of files     telescope  comments                                                                           
--------------------------------------------------------------------------------                                                  
                                                                                                                                  
50050106  Meudon            1     1.00m     Meudon PPHR; rotate 1/2-wave plate                                                    
                                                                                                                                  
50320101  Jena             21     0.90m     data as M0, used reported values                                                      
                                             of k to rereduce the data                                                            
                                                                                                                                  
50940101  Crimea           17     1.25m                                                                                           
                                                                                                                                  
50940106  Crimea           10     1.25m                                                                                           
                                                                                                                                  
50970101  Wise             16     1.00m                                                                                           
                                                                                                                                  
51010101  Kharkov           3     0.7m                                                                                            
                                                                                                                                  
51230206  Byurakan          5     0.5m                                                                                            
                                                                                                                                  
51680101  Kourovskaya       3     0.5m                                                                                            
                                                                                                                                  
51900101  Hissar           10     0.7m                                                                                            
                                                                                                                                  
52000101  Mt. Sanglok     209     1.0m      photomultiplier; dc mode                                                              
                                                                                                                                  
52000106  Mt. Sanglok      34     1.0m      photomultiplier; dc mode                                                              
                                                                                                                                  
52170101  Assy              1     1.0m                                                                                            
                                                                                                                                  
52170106  Assy             13     1.0m                                                                                            
                                                                                                                                  
52190101  Japal-Rangapur   25     1.20m     EMI 9658R; Ortec counter; assumed                                                     
                                             tau=3.0e-8sec but all rates low                                                      
                                             therefore tau irrelevant                                                             
                                                                                                                                  
53040206  Las Campanas     31     0.6m      Minipol; rotating half-wave-plate                                                     
                                                                                                                                  
53230101  Perth           148  PlanetPatrol Lowell-style photometer; dc wimode                                                    
                                                                                                                                  
53870106  Dodaira          23     0.91m     f/18; 8 channel polarimeter                                                           
                                                                                                                                  
54740101  Mt. John        196     0.61m     Mt. John photometer                                                                   
                                             data as Mi via E-mail                                                                
                                                                                                                                  
55001301  South African    32     0.50m     data as Mi                                                                            
                                                                                                                                  
55002106  Mt. Megantic     10     1.6m      Rotating 1/4-wave plate + Pockels                                                     
                                                                                                                                  
55009910  IUE              52     0.45m     Reported lat/long are fictitious.                                                     
                                             Reported magnitudes obtained with                                                    
                                             Fine Error Sensor (FES), image                                                       
                                             dissector tube which scans focal                                                     
                                             plane in cross pattern. Conversion                                                   
                                             to magnitudes done using methods                                                     
                                             described in IUE manuals.                                                            
                                                                                                                                  
55110102  Haute Provence    7     1.93m     f/5 Newtonian focus, RCA CCD                                                          
                                                                                                                                  
55590101  Catania         256     0.91m     data as Mi                                                                            
                                                                                                                                  
55680203  Mauna Kea        21     CFHT      f/4.2-prime focus; electronographic                                                   
                                                                                                                                  
55680301  Mauna Kea         5     UH-88     Tholen's photometer; data as Mi                                                       
                                             "Tinsley" photometer,RCA C31034                                                      
                                             LeCroy MVL100 pulse-amp/discrim                                                      
                                                                                                                                  
55680701  Mauna Kea        79  AirForce-24  Tholen's photometer; data as Mi                                                       
                                             "Tinsley" photometer,RCA C31034                                                      
                                             LeCroy MVL100 pulse-amp/discrim                                                      
                                                                                                                                  
55860106  Pic du Midi      18     1.0m                                                                                            
                                                                                                                                  
55860202  Pic du Midi       2     2.0m      f/5 Strand focus, RCA CCD                                                             
                                                                                                                                  
56620301  Lick              5     0.60m     data in Mi                                                                            
                                                                                                                                  
56750102  Palomar           7     Hale      prime focus, Pfuei + TI CCD                                                           
                                                                                                                                  
56860101  Mt. Lemmon       14     1.50m     data as M(std); RCA C31034                                                            
                                                                                                                                  
56880101  Lowell            9    Perkins    Lowell blue Photometer; EMI 6256                                                      
                                             Pacific Photometric Counter                                                          
                                             tau=6.0e-8                                                                           
                                                                                                                                  
56880104  Lowell            9    Perkins    Lowell Blue photometer; EMI 6256                                                      
                                             Ortec counter, tau=1.0e-7                                                            
                                                                                                                                  
56880106  Lowell            1    Perkins    VATPOL polarimeter                                                                    
                                                                                                                                  
56880201  Lowell           29   JSHall-42   Lowell blue photometer; EMI 6256                                                      
                                             Pacific Photometric Counter                                                          
                                             tau=6.0e-8; f/16                                                                     
                                                                                                                                  
56880204  Lowell            1   JSHall-42   Lowell blue photometer; EMI 6256                                                      
                                             Ortec counter tau=1.0e-7; f/16                                                       
                                                                                                                                  
56880501  Lowell           12   JSHall-42   Lowell blue photometer; EMI 6256                                                      
                                             Pacific Photometric Counter                                                          
                                             tau=6.0e-8; f/8                                                                      
                                                                                                                                  
56890106  USNO-Flagstaff   19     1.0m      VATPOL polarimeter                                                                    
                                                                                                                                  
56900101  Lowell            2   Morgan-24   Blue Photometer,EMI 6256 at 1220v                                                     
                                             Pacific Photometric Counter                                                          
                                             tau=6.0e-8                                                                           
                                                                                                                                  
56900104  Lowell            0   Morgan-24   Blue Photometer,EMI 6256 at 1300v                                                     
                                             Ortec counter, tau=1.0e-07sec                                                        
                                                                                                                                  
56950102  Kitt Peak         4     4.0m      prime focus, cryogenic CCD                                                            
                                                                                                                                  
56950202  Kitt Peak        10     2.1m      f/7.5 RCA #1 CCD                                                                      
                                                                                                                                  
56951102  McGraw-Hill        7    1.3m      f/13.5 MASCOT CCD                                                                     
                                                                                                                                  
57110102  McDonald          3     2.72m     RCA CCD                                                                               
                                                                                                                                  
58070301  Cerro Tololo    480   Yale-40     ASCAP (Automatic Single-Channel                                                       
                                             Aperture Photometer)                                                                 
                                                                                                                                  
58070801  Cerro Tololo    577  PlanetPatrol Lowell Blue photometer;EMI6256                                                        
                                             at 1220v (occ. 1225 or 1300)                                                         
                                             Pacific Photometric counter,                                                         
                                             tau=6.0e-08                                                                          
                                                                                                                                  
58090106  ESO               8     1.52m     Meudon PPHR; rotate 1/2-wave plate                                                    
                                                                                                                                  
58090302  ESO               6  Danish-1.5m  RCA SID53612 CCD                                                                      
                                                                                                                                  
58090501  ESO              72     0.50m                                                                                           
                                                                                                                                  
58200101  Tarija           47     0.60m     data in Mi                                                                            
                                                                                                                                  
58200106  Tarija           19     0.6m                                                                                            
                                                                                                                                  
58210101  Bosque Alegre    66     1.54m    data as M0, used reported k's to                                                       
                                            rereduce the data. Errors much                                                        
                                            larger than random scatter among                                                      
                                            measures on a given night because                                                     
                                            all such points were taken in a                                                       
                                            short time interval and dm and                                                        
                                            extinction were poorly determined.                                                    
                                                                                                                                  
59500301  La Palma        400 J.Kapteyn    tau=0.96e-07sec;data as Mi;E-mail                                                      
                                            2-channel photometer with filters                                                     
                                            one channel=(OH,UCNT,CN,C3,CO+)                                                       
                                            other=(BCNT,C2,RCNT,H2O+). Two                                                        
                                            channels view different parts of                                                      
                                            sky, separated by 177". Telescope                                                     
                                            offsets used to position the two                                                      
                                            different channels on particular                                                      
                                            positions at different times.                                                         
                                            In March 1986 a beam-splitter                                                         
                                            joined both channels.                                                                 
                                            Data subject to quantization                                                          
                                            errors at low signal levels.                                                          
                                            Arbitrarily assumed +/-0.5 counts                                                     
                                            for errors.  Errors may be                                                            
                                            underestimated at some locations,                                                     
                                            particularly far from nucleus                                                         
                                            where continuum very uncertain.                                                       
--------------------------------------------------------------------------------                                                  
                                                                                                                                  
                                                                                                                                  
                                                                                                                                  
VIII. ERRATA AND ADDENDA                                                                                                          
                                                                                                                                  
        In any project as large as this, errors are bound to creep in.  Some                                                      
have been caught but no doubt there are several more that we have not                                                             
found.  We welcome reports of anomalies in the data reproted here since                                                           
anomalies may be indicative of errors as well as of physically interesting                                                        
events.                                                                                                                           
                                                                                                                                  
        In addition to the data included in this archive, many other observers                                                    
submitted data which we have not been able to include because the press                                                           
of time near the completion of the archive did not allow us enough time                                                           
to reduce the data from all observers.  The choice of which datasets to                                                           
include was based largely on practical considerations.  We worked first                                                           
on the largest, most readily processed datasets, adding smaller datasets                                                          
and datasets which were more difficult to process as time permitted.  We                                                          
anticipate that at some time in the future we may produce an addendum of                                                          
other datasets which were submitted to us.                                                                                        
                                                                                                                                  
                                                                                                                                  
IX. ACKNOWLEDGEMENTS                                                                                                              
                                                                                                                                  
	The extensive program to establish a net of standard stars for the                                                               
narrow-band photometric system would have been impossible without the assis-                                                      
tance to the Discipline Specialist Team from P.V. Birch (Perth Observatory,                                                       
Australia), A. Gutierrez-Moreno (Universidad de Chile, Chile), R.L. Millis                                                        
(Lowell Observatory, U.S.A.), H. Moreno (Universidad de Chile, Chile), D.G.                                                       
Schleicher (Lowell Observatory, U.S.A.), and E. Wenderoth (Universidad de                                                         
Chile, Chile).                                                                                                                    
                                                                                                                                  
     The Discipline Specialist Team would like to particularly thank all the                                                      
observers listed in Table XIII for their efforts to make this archive a                                                           
success.  In nearly all cases, their efforts were totally voluntary,                                                              
unsupported financially by the IHW.  In addition, several individuals also                                                        
contributed by enlisting other observers and by collecting data.  Particu-                                                        
larly noteworthy was N. Kiselev who collected and submitted data from                                                             
nearly all observatories in the U.S.S.R. in addition to observing himself                                                         
both in the U.S.S.R. and in South America.                                                                                        
                                                                                                                                  
                                                                                                                                  
REFERENCES                                                                                                                        
                                                                                                                                  
A'Hearn, M.F. (1978).  Astrophys. J. 219, 768.                                                                                    
Hardorp, J. (1978).  Astron. Astrophys. 63, 383.                                                                                  
Hardorp, J. (1980a).  Astron. Astrophys. 88, 334.                                                                                 
Hardorp, J. (1980b).  Astron. Astrophys. 91, 221.                                                                                 
Hardorp, J. (1982).  Astron. Astrophys. 105, 120.                                                                                 
Hayes, D.S. and Latham, D.W. 1975 Astrophys. J. 197, 593.                                                                         
Hsu, J. and Breger, M. (1982).  Astrophys. J. 262, 732.                                                                           
Osborn, W. H., A'Hearn, M. F., Carsenty, U., Millis, R. L., Schleicher, D. G.,                                                    
   Birch, P. V., Moreno, H., and Gutierrez-Moreno, A. (1990).  Icarus,                                                            
   in press.                                                                                                                      
Sonneborn, G. S. et al. (1986).  IUE Observer's Guide.                                                                            
Thuan, T. X. and Gunn, J. E. (1976). Pub. Astron. Soc. Pac. 88, 543.                                                              
Wade, R. A., Hoessel, J. G., Elias, J. H., and Huchra, J. P. (1979).  Pub.                                                        
   Astron. Soc. Pac. 91, 35.