| Description: The spacecraft clock value at the beginning of a time period of interest. Voyager used the term Flight Data System (FDS) for this quantity, which is equivalent to the term spacecraft clock (SCLK) more commonly used by subsequent missions. The format is n/sssss:dd:mmm where n is the partition (0 if unknown), sssss is the FDS count (48 minutes per count for sssss), dd is units of 1/60 an FDS count (that is, 48 seconds per count for dd), and mmm is an optional fraction of dd (unused and value unknown). Note: Since the mmm digits are optional, it is possible (and may be common) for spacecraft_clock_start_count to be identical to spacecraft_clock_stop_count for exposure_duration values less than 48 seconds. This attribute corresponds to the keyword SPACECRAFT_CLOCK_START_COUNT in earlier versions of Voyager data products. |