Question about a fits header

[William Thompson]

alspehr at mhd3.uchicago.edu (Alanna Spehr) writes:

>I have fits files that have:

>OBS_TIME=                52917

>in their header. (Along with OBS_DATE and DATE, if it matters.)
>Can somebody tell me what the 52917 is, and how I can change it
>to something more useful? Or, is there someplace that would 
>document things like this?

Just as a guess, the number of seconds into the day?  That would work out to
14:41:57.  This sort of convention should be explained as a comment, e.g.

	OBS_TIME=                52917	/Seconds into the day (UTC)

Note, by the way that there isn't any ambiguity about an ISO-8601 entry such as

	DATE_OBS= "1996-09-04T14:41:57.000Z"

Bill Thompson