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Re: Wrong times for sunrise/sunset?
From: |
Marcin Borkowski |
Subject: |
Re: Wrong times for sunrise/sunset? |
Date: |
Sun, 20 Jan 2019 06:38:37 +0100 |
User-agent: |
mu4e 1.1.0; emacs 27.0.50 |
On 2019-01-19, at 20:17, Pierpaolo Bernardi <olopierpa@gmail.com> wrote:
> Il giorno 19 gennaio 2019, alle ore 16:27, Marcin Borkowski <mbork@mbork.pl>
> 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