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 2 Data:  Later submissions included the images from March 7 (189) and March 10 (51) before and after the encounter period (March 9 (7:20:54.8), 1986). These data were given a file description to indicate if they were PRE or POST encounter. The data, in its original form, is included but with a new filenaming scheme which was 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 was 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 times. 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 is assumed to be the same as for Vega 1 data. 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 2, the assumed switch-on times (UT0) were March 7, 3h47m25s and for March 10, 5h48m14s; these values are given as COMMENTs in the FITS header. The state vectors for Vega 2 in equatorial XYZ coordinates are as follows:   X:-63031872.6 Y:-107676032.6 Z:+1048764. (in km) V(X):+31.6486 V(Y):-11.6669 V(Z):-1.8879 (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 subtract 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.  For two of the filtered files, the submitted FITS header had errors in the TONBHRDW values; these were eliminated. In the case of 5 other files (1198, 1202, 1206, 1210, 1214), no FITS information was sent; the FITS header was constructed from the corresponding original data file except that a CHECKSUM value was added to identify the image correctly.  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.

Confidence Level Overview:  N/A