Data Set Overview
    =================
    Encounter data for Vega-2 consisted of two files:
    DSFAST27 and Dvg2CLN1.  The data were submitted by
    the Univ of Chicago group along with hard copy
    versions of the operating manual and a preprint of
    the results.
 
     The dsfast27 file includes all the fast telemetry
    data (data obtained every second).  The fast
    telemetry data covers the entire Halley's comet
    encounter, lasting approximately four hours.  The
    telemetry noise events have not been removed from the
    data.  Each readout includes; 1)the time at which
    data was obtained in seconds (given in time since the
    Vega launch date),and the Blissi clock described in
    the technical manual, 2) Two eight integer status
    commands also described in the Ducma Technical
    Manual, 3) two temperatures,the detector temperature
    and the electronic temperature explained in the
    technical manual, 4) the dust events given as ten
    integers which represent counts in each of four
    different thresholds,M4-M1,as well as the
    anticoincident counts,M4NV-M1NV, and the two V
    detector counts, VL and VH, which register noise
    events.  More detailed explanations may be found in
    the Ducma technical manual which is available through
    PDS-SBN.  The masses corresponding to thresholds M1
    through M4 are given below:
 
        M1: 1.5x10**-13 g
    	M2: 5.6x10**-11 g
    	M3: 1.6x10**-9 g
        M4: 4.0x10
 
 
    Dvg2CLN1 file includes the encounter data without any
    information about status commands and temperature
    variations.  The noise spikes and accidental
    calibration events have been removed.  This file is
    designed for easy data analysis and lists simply the
    time of an event in seconds and the total counts in
    each threshold, M4-M1, the anticoincident events,
    M4NV-M1NV, and the noise events,VL and VH, all
    obtained during that time interval.
 
     Below are charts to help in the conversion of BLISSI
    clock times for Vega2 to DUCMA clock times and
    'calendar time'.
 
    DUCMA times are given in seconds after launch
    BLISSI times are given in seconds
 
 
 
Vega2
DUCMA start time: Dec. 21 1984 10:29:46
from file dsfast27.tab
------------+-----------+--------------------------+--------------------+
 DUCMA time |BLISSI time|    DUCMA Time to CA 	   |      Real time	|
  (seconds) | (seconds)	| (seconds) |(DD hh:mm:ss) | (YY-MM-DDThh:mm:ss)|
------------+-----------+-----------+--------------+--------------------+
  37478720  |   49156   |   785332  | 09 02:08:52  |  86-02-28T05:11:08	|
@ 37483380  |   53818 	|   780672  | 09 00:51:12  |  86-02-28T06:28:48	|
@ 37483380  |   37435 	|   780672  | 09 00:51:12  |  86-02-28T06:28:48	|
  37483384  |   37436   |   780668  | 09 00:51:08  |  86-02-28T06:28:52	|
  37486588  |   38595	|   777464  | 08 23:57:44  |  86-02-28T07:22:16	|
  38079280  |       1	|   184772  | 02 03:19:32  |  86-03-07T04:00:28	|
  38086472  |    7191	|   177580  | 02 01:19:40  |  86-03-07T06:00:20	|
  38173960  |       5	|    90092  | 01 01:01:32  |  86-03-08T06:18:28	|
  38181148  |    7194	|    82904  | 00 23:01:44  |  86-03-08T08:18:16	|
  38252812  |       1	|    11240  | 00 03:07:20  |  86-03-09T04:12:40	|
* 38264052  |   11242   |        0  | 00 00:00:00  |  86-03-09T07:20:00 |
  38268860  |   16049	|     4808  | 00 01:20:08  |  86-03-09T08:40:08	|
------------+-----------+-----------+--------------+--------------------+
 
*-times of Closest Approach (CA)
 
@-BLISSI clock apparently reset from 53818 to 37435 during 4 second
	DUCMA time period beginning at 37483380 seconds, resulting
	in two very different BLISSI clock values 'mapping' to the
        same DUCMA time and Real time.

Confidence Level Overview
    =========================
      N/A