From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Marcin Borkowski Newsgroups: gmane.emacs.help Subject: Re: Wrong times for sunrise/sunset? Date: Sun, 20 Jan 2019 06:38:37 +0100 Message-ID: <87k1izoplu.fsf@mbork.pl> References: NNTP-Posting-Host: ciao.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ciao.gmane.org 1547962807 65347 195.159.176.228 (20 Jan 2019 05:40:07 GMT) X-Complaints-To: usenet@ciao.gmane.org NNTP-Posting-Date: Sun, 20 Jan 2019 05:40:07 +0000 (UTC) User-Agent: mu4e 1.1.0; emacs 27.0.50 Cc: "help-gnu-emacs@gnu org" To: Pierpaolo Bernardi Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sun Jan 20 06:40:04 2019 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:256) (Exim 4.84_2) (envelope-from ) id 1gl5pz-000GzP-5G for geh-help-gnu-emacs@m.gmane.org; Sun, 20 Jan 2019 06:40:03 +0100 Original-Received: from localhost ([127.0.0.1]:35719 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gl5q8-0002gm-1Q for geh-help-gnu-emacs@m.gmane.org; Sun, 20 Jan 2019 00:40:12 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:54143) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gl5pg-0002gd-4A for help-gnu-emacs@gnu.org; Sun, 20 Jan 2019 00:39:45 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gl5pf-0006wL-3f for help-gnu-emacs@gnu.org; Sun, 20 Jan 2019 00:39:44 -0500 Original-Received: from mail.mojserwer.eu ([195.110.48.8]:38158) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gl5pe-0006f3-QS for help-gnu-emacs@gnu.org; Sun, 20 Jan 2019 00:39:43 -0500 Original-Received: from localhost (localhost [127.0.0.1]) by mail.mojserwer.eu (Postfix) with ESMTP id 9D3EFE6BE2; Sun, 20 Jan 2019 06:39:18 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at mail.mojserwer.eu Original-Received: from mail.mojserwer.eu ([127.0.0.1]) by localhost (mail.mojserwer.eu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id aEcLpuZbS-iQ; Sun, 20 Jan 2019 06:39:15 +0100 (CET) Original-Received: from localhost (static-dwadziewiec-jedenpiec7.echostar.pl [109.232.29.157]) by mail.mojserwer.eu (Postfix) with ESMTPSA id 48C80E6650; Sun, 20 Jan 2019 06:39:15 +0100 (CET) In-reply-to: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 195.110.48.8 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.org gmane.emacs.help:119127 Archived-At: On 2019-01-19, at 20:17, Pierpaolo Bernardi wrote: > Il giorno 19 gennaio 2019, alle ore 16:27, Marcin Borkowski ha scritto: > >>Hello, >>C-u M-x sunrise-sunset (and today's date) says > >>I also noticed that other online services give yet other results. >>Anybody knows why the difference(s)? > > See https://lists.gnu.org/archive/html/help-gnu-emacs/2016-07/msg00321.html > > Hth Yes, that helps, thanks. Out of curiosity - Michael Heerdegen writes there: --8<---------------cut here---------------start------------->8--- AFAIK the Emacs calculation is exact - it respects all astronomical effects I know of. But it doesn't try hard to round to whole minutes correctly, so the result may differ from the actual event by an epsilon, where epsilon < 1 min I think. --8<---------------cut here---------------end--------------->8--- But the differences I can see are a few minutes. Why, after takign care of all astronomical effects, is "rounding to whole minutes correctly" even an issue? (I understand that I know very little abot time calculations and such, and I understand they are difficult. I'd just like to know.) Best, -- Marcin Borkowski http://mbork.pl