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From: roberts@stsci.EDU (Jim Roberts)
Newsgroups: comp.binaries.ibm.pc.d
Subject: Re: (Astronomical) Julian Date Source Wanted
Message-ID: <2494@nemesis.stsci.edu>
Date: 15 Apr 91 21:59:47 GMT
References: <9873.2808dac2@ohstpy.mps.ohio-state.edu> <40790006@hpcvra.cv.hp.com.>
Reply-To: roberts@stsci.EDU (Jim Roberts)
Organization: Space Telescope Science Institute, Baltimore, MD 21218
Lines: 19

In article <40790006@hpcvra.cv.hp.com.> everett@hpcvra.cv.hp.com. (Everett Kaser) writes:
>Just out of curiousity, what's the difference between Astronomical and 
>USGovernment Julian dates?

Strictly speaking the astronomical quantity is the Julian day number,
which is the number of ephemieris days that have elapsed at the
previous 12h ET since 12h ET on 1 Jan 4713 BCE.

You'll have to specify what you mean by US Govt Julian dates.  It is
common to count the days from 1 Jan 1900, without tying them to noon,
or to Zulu time.  Some even confuse day of year with Julian date.

Right now,
	Julian day number = 2448362.415
	DOY		  = 105


-- 
Jim Roberts	roberts@stsci.edu	scivax::roberts