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From: nachum@uiucdcs.CS.UIUC.EDU
Newsgroups: net.religion.jewish
Subject: Re: ten tal u'matar
Message-ID: <44500030@uiucdcs>
Date: Thu, 12-Dec-85 12:34:00 EST
Article-I.D.: uiucdcs.44500030
Posted: Thu Dec 12 12:34:00 1985
Date-Received: Mon, 16-Dec-85 19:39:41 EST
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Nf-From: uiucdcs.CS.UIUC.EDU!nachum    Dec 12 11:34:00 1985


/* Written 11:39 pm  Dec 10, 1985 by dave@lsuc.UUCP in uiucdcs:net.religion.jewish */
I've always wondered about this one.
To my knowledge, this is the only instance in all of Jewish
observance where the solar calendar, rather than the lunar
(Jewish) calendar, is used to define a date; hence it's always
December 4.

Why?

Dave Sherman
The Law Society of Upper Canada
-- 
{  ihnp4!utzoo  pesnta  utcs  hcr  decvax!utcsri  }  !lsuc!dave
/* End of text from uiucdcs:net.religion.jewish */

Not always Dec 4th, but sometimes the 5th.
Actually, the date is 60 days after an approximation to the
Autumn Equinox.  I believe the talmudic approximation (365.25 days/year)
is about two weeks off from the real equinox this century.
The Gregorian calendar uses a better approximation (365.24 days/year),
hence the constantly increasing discrepancy (1 day/century).
The "blessing of the sun" every 28 years (when the Spring quinox
returns to the same day of week and time of day) derives from the same
approximation of the solar year.