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From: abs@nbc1.UUCP
Newsgroups: net.misc
Subject: Re: Re: Counting years
Message-ID: <160@nbc1.UUCP>
Date: Fri, 29-Aug-86 13:09:19 EDT
Article-I.D.: nbc1.160
Posted: Fri Aug 29 13:09:19 1986
Date-Received: Mon, 1-Sep-86 01:27:14 EDT
References: <1408@tektools.UUCP> <6018@fortune.UUCP> <142@csustan.UUCP> <20804@styx.UUCP>
Distribution: net
Organization: NBC Computer Imaging, New York, NY
Lines: 33

> In article <142@csustan.UUCP> smdev@csustan.UUCP (Scott Hazen Mueller) writes:
> > . . .  
> > The Jewish calendar is an obscure little thing (with a year currently
> > in the 5-or-6 thousands) based on lunar cycles.  Certain holidays, such as
> > Passover and, by definition, Easter (the first Sunday after the first night
> > of Passover) are based on this lunar calendar [...]
> 
> Not obscure; merely lunar. (Though the occasional "leap months" do tend
> to make calculation more interesting.) The current Jewish year is
> something like 5742. Somebody will no doubt definitively correct this.

And here's the correction:  it's currently 5745.

Also:  the Jewish calendar is not strictly Lunar (as is the Moslem), but
is luni-solar.  Although the months are based strictly on the phases of the
moon, there is a "leap month" added 7 times every 19 years.  (This is
where the "solar" part comes in.)  So although months tend to wander slightly
(when compared to the Christian calendar), it permits religious holidays
to occur during the proper time of the year.

The Moslem calendar, on the other hand, is purely lunar, and the months
wander.  Ramadan can be in winter one year, and several years later (14?)
it will have cycled around to summer.

The Jewish year is based on the date of the creation of the world
(gleaned from careful discussion and analysis of biblical sources).

Note also that Easter is no longer tied to Passover.  One of the popes
(Gregory?) devised an alternate algorithm for calculating when Easter
occurs (see Knuth Volume I for the exact algorithm).
-- 
Andrew Siegel, N2CN		NBC Computer Imaging, New York, NY
philabs!nbc1!abs		(212)664-5776