Notes on representing times in the JSOC

Internal time represented as a double holding the number of seconds since 00:00:00.0 on Jan. 1, 1977 (TAI). External representations are in the form yyyy.mm.dd_hh:mm:ss.s_UTC. The "zone" may be _UTC, _TAI, etc. If it is omitted it is taken to be UTC.

The conversion from text to internal format follows the rules developed for the SOHO/MDI program and can be found at http://soi.stanford.edu/technotes/94.116.html

The _UTC extension is the default and may be omitted.

JD_ and MJD_ formats are allowed but seldom used.

The ":ss.s" may be omitted but the minutes may not. This is a long standing bug (or deficiency). If a fraction of a day is given rather than hh:mm then the "_" is replaced with a "." so _12:00 could also be expressed as .5.

Note that this time format is not ISO 8601 compliant.

Do not use the two-digit format for year. It will likely give the wrong century (OK from 1910 until 2009) after launch.

When entering times in DRMS, such as in default times in JSD files, the form:

is preferred unless the TAI time is explicitly needed in which case the form should be:

When entering format strings to be used for printing time type data in DRMS, such as in JSD files, the format may be one of the timezone codes in the SOI technote referenced above. The usual choices are UTC or TAI.

JsocWiki: JsocTimes (last edited 2013-05-01 04:35:23 by localhost)