At 13:31 -0400 8/15/05, Mark Reed wrote: >More specifically, that's the astronomical Julian Day, or JD, and JD 0 began >at noon Universal Time (a.k.a. GMT) on January 1, 4713 BC in the Julian >calendar. Sometimes this is called the Julian Astronomical Day, or JAD, to >distinguish it from various other misappropriations of the term "julian >day/date".
If anyone gets serious about Julian dates there is also the Modified Julian Date, MJD, used by the US military and others. It differs from the JAD above by a large well-defined integer plus 1/2. The result is a day that begins at midnight and starts at a more recent date that I don't remember. It's not Jan 0, 1970 though. There is also ephemeris time which is the absolute clock that makes Newtonian mechanics come out correctly regardless of changes in the rotational speed of planet Earth. Don't even think about supporting that. -- --> Halloween == Oct 31 == Dec 25 == Christmas <--
