Data Set Information
DATA_SET_NAME VEGA1 TV SYSTEM IMAGES PROCESSED BY KFKI V1.0
DATA_SET_ID VEGA1-C-TVS-3-RDR-HALLEY-PROCESSED-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview: The TVS data from KFKI came in various stages. The initial submission from KFKI was completely replaced in the fall 1992. At that time, additional processed data with aspect and range corrections were included. The original filenaming scheme was preserved except for changing the leading filename character and expressing the aspect ratio as 'a'. Mission data description KFKI New LPL-NO Vega 1 original 63 images w01114 T01114 1114 filtered 32 images w02114 T02114 2114 filtered with 4/3 aspect corr w211443 T2114A filtered, aspect and range corr w211443r T2114AR sharpened 32 images w09114 T09114 9114 sharpened with 4/3 aspect corr w911443 T9114A sharpened, aspect and range corr w911443r T9114AR flat field w02769 T02769 2769Vega 2 original 11 images w01174 T01174 1174 filtered 11 images w11174 T11174 2174 flat fields w01301 T01301 Vega 1 Data: Later submissions included the images from March 5 (60) and March 7 (186) before and after the encounter period (March 6 (7:21:00.9), 1986). These data were given a file description to indicate if they were PRE or POST encounter. The data is included in its original form but with a new filenaming scheme (TPREnnnn and TPOSnnnn), unique to the data set. The data were sent as a separate image file (8 bit) with an ascii description of the header information. An IHW-FITS file was created from this data in the style of the previous submissions, and approximate times were calculated from the TONBHRDW value provided with the data. Since this is a relative value, the switch-on time was taken from a preprint by Laszlo Varhalmi (KFKI) and a previous communication with KFKI also gave the state vector for each spacecraft during the encounter. Note that the switch-on times are then given as UT : Moscow time - 3 hours and a 'light travel time' must be subtracted to match published values. The algorithm for the midpoint of any exposure was calculated as follows: UT (midpoint) : UT0+5.5+TONBHRDW/4.766485-T(exp)-T(loc)+T(exp)/2 (second). Note the clock count rate comes from a fit of times to original 63 images. We have taken the 5.5 s correction from Varhalmi as due to a memory readout; another correction of 1.6 s called T (loc) was needed if the image was less than the full array which is a process time to find and transmit the data. For Vega 1, the assumed switch-on times were March 5, 5h48m8s and for March 7, 7h 58m57s; these values are given as COMMENTs in the FITS header. The state vectors for Vega 1 in equatorial XYZ coordinates are as follows: X:-51480466.2 Y:-106677747.1 Z:+4023544.7 (in km) V(X):+33.4265 V(Y):-10.6418 V(Z):-2.7059 (in km/sec) It was asuumed these were barycentric coordinates and the linear velocities were used to estimate the coordinates for the new dates and times. Appropriate values from the Nautical Almanac for 1986 were used to make the earth correction and eventually estimate the light travel time correction. It was determined that the calculated UT times are consistent with the published values within 3 seconds; as such we leave the TIME-OBS keyword value (midpoint day fraction required by the IHW) as 4 significant digits. Unfortunately, in the processing it was discovered that 3 images in POST submissions from Vega 1 had inconsistent descriptions and were rejected. Also, an error in the times provided in the revised FITS headers for the original 24 images (Nos 1-20, 25, 33, 39, 61) was corected at SBN. In one case, T01111, the FITS header had incorrect values for the exposure and it is not clear that the data is correctly matched with the header. Abergel, J., Bertaux, G., Avanessov, G.A., Tarnopolsky, V.I., and Zhulov, B.S., 1987, Appl. Opt., 26, No.26, 4457-4468. Kondor, A., 1990, MPAE-W-100-90-04. Merenyi, E., Foldy, C., Szego, K., Toth, I. and Kondor, A., 1990, Icarus, 86, 9-20.
DATA_SET_RELEASE_DATE 3000-01-01T00:00:00.000Z
START_TIME 1986-03-05T06:01:09.120Z
STOP_TIME 1986-03-07T10:06:31.680Z
MISSION_NAME VEGA 1
MISSION_START_DATE 1984-12-15T12:00:00.000Z
MISSION_STOP_DATE 1986-04-01T12:00:00.000Z
TARGET_NAME HALLEY
TARGET_TYPE COMET
INSTRUMENT_HOST_ID VEGA1
INSTRUMENT_NAME TELEVISION SYSTEM
INSTRUMENT_ID TVS
INSTRUMENT_TYPE CAMERA
NODE_NAME Small Bodies
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE Confidence Level Overview: N/A
CITATION_DESCRIPTION Abergel J., Bertaux G., Avanessov G.A., Tarnopolsky V.I., Zhulov B.S., Kondor A., Merenyi E., Foldy C., Szego K., Toth, I., and A. V. Dyachkov, VEGA1 TV SYSTEM IMAGES PROCESSED BY KFKI V1.0, VEGA1-C-TVS-3-RDR-HALLEY-PROCESSED-V1.0, NASA Planetary Data System, 1997
ABSTRACT_TEXT The TVS data from KFKI came in various stages. The initial submission from KFKI was completely replaced in the fall 1992. At that time, additional processed data with aspect and range corrections were included. The original filenaming scheme was preserved except for changing the leading filename character and expressing the aspect ratio as 'a'.
PRODUCER_FULL_NAME INTERNATIONAL HALLEY WATCH
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