From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: ken Newsgroups: gmane.emacs.help Subject: Re: Wrong times for sunrise/sunset? Date: Sun, 20 Jan 2019 00:52:39 -0500 Message-ID: <9786bdc7-d02a-7433-1e8a-a66708dc6483@mousecar.com> References: <87pnssoeiz.fsf@mbork.pl> Reply-To: gebser@mousecar.com NNTP-Posting-Host: ciao.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: ciao.gmane.org 1547963592 71172 195.159.176.228 (20 Jan 2019 05:53:12 GMT) X-Complaints-To: usenet@ciao.gmane.org NNTP-Posting-Date: Sun, 20 Jan 2019 05:53:12 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sun Jan 20 06:53:10 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 1gl62f-000IVg-Sj for geh-help-gnu-emacs@m.gmane.org; Sun, 20 Jan 2019 06:53:10 +0100 Original-Received: from localhost ([127.0.0.1]:35833 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gl62o-0004HQ-QF for geh-help-gnu-emacs@m.gmane.org; Sun, 20 Jan 2019 00:53:18 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:55910) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gl62J-0004HH-Da for help-gnu-emacs@gnu.org; Sun, 20 Jan 2019 00:52:48 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gl62I-0000oy-AN for help-gnu-emacs@gnu.org; Sun, 20 Jan 2019 00:52:47 -0500 Original-Received: from mout.perfora.net ([74.208.4.196]:60547) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gl62I-0000nF-3c for help-gnu-emacs@gnu.org; Sun, 20 Jan 2019 00:52:46 -0500 Original-Received: from [192.168.0.17] ([96.27.75.237]) by mrelay.perfora.net (mreueus001 [74.208.5.2]) with ESMTPSA (Nemesis) id 0LzIiF-1hGQah3Cr3-014SR5 for ; Sun, 20 Jan 2019 06:52:42 +0100 In-Reply-To: <87pnssoeiz.fsf@mbork.pl> Content-Language: en-US X-Provags-ID: V03:K1:x6HLzVnyerFjYmtNVEdU1nhIzwHdnm2rAiHA75kDk+IvGD/adbA U7C4zP/HCMLRH2iuG28CWIUmOYI8FBZgDNhCyiP5kOvZs0kjIOvqmCxPG7jvAKnrra5EHT4 X0R+InTkN/rLHMfYoo+h30N/HbXR0KeRaKHjEHegMgwwHRRGalV03WzZl89zFGNlzrjBFnr bqygWG7fbzwsu1bB2qbdg== X-UI-Out-Filterresults: notjunk:1;V03:K0:rdzu3X6NqRA=:zGLPePOiX7TSDHLB2Qps0F FoK9NlIPwm/8CtyDGM5g0YOCBPbMyBv2MJ+WOhBH71dej3e4HqnOmQqTa7rz2QRTWkejz1Ioc ZHGkXVV+yVErzGIry5GHpAYsPp1arDFyQnjXFxI+WmMwzFOq3jyCSxSWLY2tvaOzKznH3igxx W7nzXITlHrr3waveBetf0UbMIwpWAn3fW1BMZGYlYZk2eVU6M/gLAM8DJmYKicGxmTdiAo4Ln nqnVR1swvSPKoFdsBuPDvT8LRgkpZ4ejHTErhuSNiejRtdAHKNtLTCRouULMq2BrxQtiP2T8Y qxjON0gqKCtMavcEEZ7elwo9xzXMwe9N050EdlC/Y4cxThyLcwX5ExalHxGA7Kq12WOhUYBJA 47PSShSE7mXfo/qaNWF3k2uFIPOmA+BmkNStIYuJmu2Z0I5OKrBv3FxJgAtCDfvkyaMdjh1k1 t40MA/8X+eqRLPjgWYaecOqL9o7wF/VVGAnMljI6qsEKQ/kHuE3cjM7U9XAs1ORIONEnHtNaZ k2P2t8erHgsuoMrI5m0vPySErmvOQzOKaWBmPIaHJMVrMY/MxCjYihM5xny5Ow03xO2fDd8Nr l1HgtnYwx9Q06pb/Ky11W8aBpQXNC7zvgXpLTAsBpPMrL5oET7Ccnsz3MuGER4MwiiDQw36E2 zaa2ob2G0TP72xQfNEzyykDfWmeTBF4U3Q8i4TA4wFKfb6I3zVQslr1sREP4U8h3xS0GiJ4Ns FXGHne2TjQ6V4Y24k9Ha0BV5JEZfT9N2vx41D/tImzpHMtmX9qdIecnKM7E= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 74.208.4.196 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:119128 Archived-At: On 1/19/19 10:25 AM, Marcin Borkowski wrote: > Hello, > > C-u M-x sunrise-sunset (and today's date) says: > > --8<---------------cut here---------------start------------->8--- > Sat, Jan 19, 2019: Sunrise 7:54am (CET), sunset 4:13pm (CET) at Poznań, > Poland (8:19 hrs daylight) > --8<---------------cut here---------------end--------------->8--- > > Here are my settings: > > --8<---------------cut here---------------start------------->8--- > (setq calendar-latitude 52.4) > (setq calendar-longitude 16.917) > (setq calendar-location-name "Poznań, Poland") > --8<---------------cut here---------------end--------------->8--- > > (BTW, if anyone is ever near here, please drop me a line - we might be > able to meet in person;-)). > > And C-u M-: calendar-time-zone says (correctly) 60. > > However, https://www.timeanddate.com/astronomy/poland/poznan (for today) > says: > > --8<---------------cut here---------------start------------->8--- > Sunrise Today: 07:51↑ 124° Southeast > Sunset Today: 16:14↑ 237° Southwest > --8<---------------cut here---------------end--------------->8--- > > I also noticed that other online services give yet other results. > > Anybody knows why the difference(s)? > > TIA, > > -- > Marcin Borkowski > http://mbork.pl Reading on sunrise-sunset a long time ago, I was given to understand that, while the calculations are unambiguous, the perception of those times is open to interpretation.  Especially when the sun (and other astronomical objects) is low to the horizon, the Earth's atmosphere acts as a lens, enabling us to see the sun (etc.) even before and after it is in our straight line-of-sight.  That is, the atmosphere's lensing effect allows us to see a little bit over the horizon.  The calculations performed by emacs do not compensate for the atmospheric magic.  But other sources, rather than being accused of inaccuracy by the public who might look out the window, typically amend the purely physical reckoning to accommodate earthly perceptions. hth, ken