Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!pwp
From: pwp@iuvax.cs.indiana.edu
Newsgroups: comp.sys.atari.st
Subject: Re: Julian Date
Message-ID: <36500066@iuvax>
Date: 22 Jul 89 01:06:00 GMT
References: <133738@<1989Jul21>
Organization: Indiana University CSCI, Bloomington
Lines: 13
Nf-ID: #R:<1989Jul21:-13373800:iuvax:36500066:000:737
Nf-From: iuvax.cs.indiana.edu!pwp    Jul 21 20:06:00 1989


The Julian day number is the number of days since 4004 BC or when ever it was
that someone calculated that God created the earth. This system was developed
by astronomers who need to deal with historical records recorded under
different calander systems. Thus someone studying some old record can
translate the dates to Julian days and other astronomers who know nothing
about the calcander used in the original record can understand the date. 4004
BC is far enough back that all historical records recieve a positive Julian
date.

Since the current Julian day is a hugh integer, computer programs often use
some other starting point, but call the integer day number the Julian day
anyway. This practice occasionally leads to confusion.