Data Set Overview:  McDonald Observatory Faint Comet Survey Gas Data This study presents spectral data from 152 observations of 17 cometsobtained using an Intensified Dissector Scanner spectrograph at theMcDonald Observatory. A full description of these data and the reduction process, along withHaser model production rates can be found in Cochran et al. (1992)[COCHRANETAL1992].  Parameters:All essential parameters including fluxes, aperture positions and size,comet heliocentric and geocentric positions and heliocentric radialvelocity are provided in this PDS submission. The fluorescenceefficiencies used for the column density calculations can be found inCochran et al. (1992) [COCHRANETAL1992], along with additional HaserModel parameters and estimated production rates. Measures of thecometary continuum and gas-to-dust ratios are available in Storrset al. (1992) [STORRSETAL1992]. Processing:The processing carried out on the McDonald Observatory Faint Comet Surveyare described elsewhere [COCHRANETAL1992; STORRSETAL1992; COCHRAN1987]. Using standard star measurements, the raw data counts were converted toflux units. The separate sky spectrum was then subtracted from theobject spectra, weighting by the strength of the 5577 A night sky lineto account for different exposure times. A color corrected solar spectrumwas then removed and the various bands were integrated in order to measurethe emission band intensities. The fluorescence efficiencies given below[COCHRANETAL1992] were then used to convert to column densities. Molecule ConstantCN f(dR/dt) heliocentricC3 12.42CH 12.98C2 (delta NU : 1) 12.62C2 (delta NU : 0) 12.35NH2 (0,10,0) 13.73 Data: 1) fluxcdmc.tab: cometocentric aperture positions and fluxes and column densities for all dates.3) parammc.tab: Contains the parameters associated with the observations. In calculating the flux and column densities for the six molecular speciesthe following bandpasses (from Table I of COCHRANETAL1992) were used: molecule Bandpass (A)CN (delta NU : 0) 3830-3905C3 3975-4150CH 4280-4340C2 (delta NU : 1) 4460-4770C2 (delta NU : 0) 4860-5185NH2 (0,10,0) 5675-5760  Coverage: The following 17 comets are included in this data set:  Principal Obsolete Number, Type and Name Designation Designation(s) ------------------------------ ----------- -------------- 49P/Arend-Rigaux 1951 C2 1984k C/Austin 1982 M1 1982g C/Austin 1984 N1 1984i C/Bradfield 1987 P1 1987s 67P/Churyumov-Gerasimenko 1969 R1 1982f 26P/Grigg-Skjellerup 1922 K1 1982a, 1986m 68P/Klemola 1965 U1 1987i 22P/Kopff 1906 Q1 1982k, 1988k C/Levy-Rudenko 1984 V1 1984t 25P/Neujmin 1 1913 R2 1984c C/Nishikawa-Takamizawa-Tago 1987 B1 1987c 24P/Schaumasse 1911 X1 1984m C/Sorrells 1986 V1 1986n 64P/Swift-Gehrels 1889 W1 1981j 9P/Tempel 1 1867 G1 1982j 10P/Tempel 2 1873 N1 1982d 1987g 62P/Tsuchinshan 1 1965 A1 1984p The obsolete designations have been removed from the data files andreplaced with the IAU principal designations.  Ancillary Data:A complementary dataset regarding the continuum spectral measurementsand an ad hoc measure of the cometary dust emission, A(theta)*f*rho[AHEARNETAL1984], can be found in STORRSETAL1992.  Media/Format:This dataset is released in the form of ASCII files which may bestored on disk or other magnetic medium and which may bedistributed by ftp, email, real-time access by remote login, or bywhatever means is most convenient.

Review:The MOFCS has been reviewed internally by Anita Cochran prior to releaseto the planetary community. An external PDS peer review was held in lateSeptember 1998.