From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.bugs Subject: cal-persia.el disagrees with Iranian calendar in A.D. 2025 Date: Wed, 30 Mar 2005 12:29:33 -0500 Message-ID: <87sm2d82ki.fsf@penguin.cs.ucla.edu> NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Trace: sea.gmane.org 1112204052 22480 80.91.229.2 (30 Mar 2005 17:34:12 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Wed, 30 Mar 2005 17:34:12 +0000 (UTC) Cc: bug-gnu-emacs@gnu.org Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed Mar 30 19:34:04 2005 Return-path: Original-Received: from lists.gnu.org ([199.232.76.165]) by ciao.gmane.org with esmtp (Exim 4.43) id 1DGh4g-000103-EW for geb-bug-gnu-emacs@m.gmane.org; Wed, 30 Mar 2005 19:33:51 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1DGhLC-0002KJ-6G for geb-bug-gnu-emacs@m.gmane.org; Wed, 30 Mar 2005 12:50:54 -0500 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1DGhK1-0001vw-Qb for bug-gnu-emacs@gnu.org; Wed, 30 Mar 2005 12:49:41 -0500 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1DGhJu-0001rs-HU for bug-gnu-emacs@gnu.org; Wed, 30 Mar 2005 12:49:35 -0500 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1DGhJt-0001nj-5o for bug-gnu-emacs@gnu.org; Wed, 30 Mar 2005 12:49:33 -0500 Original-Received: from [131.179.128.19] (helo=kiwi.cs.ucla.edu) by monty-python.gnu.org with esmtp (Exim 4.34) id 1DGh1C-0007s8-FX for bug-gnu-emacs@gnu.org; Wed, 30 Mar 2005 12:30:22 -0500 Original-Received: from penguin.cs.ucla.edu (Penguin.CS.UCLA.EDU [131.179.64.200]) by kiwi.cs.ucla.edu (8.11.7p1+Sun/8.11.7/UCLACS-5.2) with ESMTP id j2UHTXX15415; Wed, 30 Mar 2005 09:29:33 -0800 (PST) Original-Received: from eggert by penguin.cs.ucla.edu with local (Exim 3.35 #1 (Debian)) id 1DGh0X-0005MN-00; Wed, 30 Mar 2005 09:29:33 -0800 Original-To: "Edward M. Reingold" User-Agent: Gnus/5.1006 (Gnus v5.10.6) Emacs/21.4 (gnu/linux) X-BeenThere: bug-gnu-emacs@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:11015 X-Report-Spam: http://spam.gmane.org/gmane.emacs.bugs:11015 A time-zone database user reported a bug for the year 2025 in Iran. This appears to be due to a disagreement between GNU Emacs's cal-persia.el and the user's (German) source for the Persian calendar. The problem occurs both with Emacs 21.4 and CVS head. I enclose the user's email below. I confirmed that (calendar-gregorian-from-absolute (calendar-absolute-from-persian '(1 1 1404))) returns (3 20 2025), so it does appear that cal-persia disagrees with his source, which says that 1 Farvardin 1404 corresponds to 21 March 2025. I don't know whether this should be a code fix or an enhancement (cal-iran.el, say?). > From: Oscar van Vlijmen > Subject: Iran calculated DST dates > Date: Wed, 30 Mar 2005 14:38:46 +0200 >=20 > I checked the DST on/off dates for Iran. > It appears that the dates were calculated with the arithmetic 'Persian' > calendar in mind. Since 1925 an astronomical calendar is in use, so I rea= d. > There is one day difference between these two calendar systems in the > Gregorian year 2025, so there is one error in the list of DST rules for I= ran > if indeed the astronomical calendar system is used. >=20 > The astronomical Iranian calendar has 1 Farvardin 1404 on 21 March 2025 > Gregorian, so DST on is per 22 March 2025 0:00, and 30 Shahrivar 1404 is = on > 21 September 2025 Gregorian, so DST off is per 22 September 2025 Gregoria= n. >=20 > The vernal equinox in 2025 Gregorian is at around 09:01 UTC on March 20, = so > around 12:27 Tehran 'solar' time. This is past 12:00, hence 1 Farvardin is > on March 21. >=20 > A long article about the Iranian calendar (in German): > Iranische Zeitrechnungen, Nikolaus A. B=C3=A4r, 2004. > See the chapter "Der neuiranische Kalender", with a French translation of > the 1925 law. > http://www.nabkal.de/irankal.html >=20 > I checked the Iranian calendar dates with the Java application by > Reingold/Dershowitz, version 2.1. > http://emr.cs.iit.edu/home/reingold/calendar-book/Calendrica.html > And the mentioned vernal equinox date/time with 2 different astronomical > programs. >=20 > Oscar van Vlijmen > 2005-03-30 >=20