puttime -- Compute occurrence times of FGS astrometry data.
FGS astrometry files can represent one of several different observation types. These types are DARK, BKGD, POSITIONAL, POSITIONAL MOVING, TRANSFER FUNCTION, and 'TRANSFER FUNCTION MOVING'. Each type occurs at one of two speeds--4 kilobits per second or 32 kilobits per second. However, the nature of the telemetry stream makes it difficult to determine what event happened at what time and there is little information linking the raw data with occurrence times.
Puttime will calculate occurrence times--in milliseconds from the beginning of the observation--and write those times into the original FGS data file.
Times represent different raw data depending on the observation mode being used. For example, DARK, BKGD, and TRANSFER MOVING occur at both 4 kbps and 32 kbps, and the times represent groups that have photomultiplier counts. For 4-kbps POSITIONAL and POSITIONAL MOVING astrometry, the times represent occurrences of star sensor averaging times, however, for 32-kbps POSITIONAL and POSITIONAL MOVING, the times represent star sensor position readings. Times represent photomultiplier counts for 'TRANSFER FUNCTION' observations.
The calculated times are placed in the appropriate group of the original FGS file, and the keyword TIMED is set to "T". Before this task can be rerun the value of the keyword TIMED must be changed to "F".
1. Put observation times into the FGS file f1m.a1h.
fg> puttime f1m.a1h