GNU bug report logs - #61460
30.0.50; Calendar shows eclipse for quarter moon

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Package: emacs;

Reported by: Ulrich Mueller <ulm <at> gentoo.org>

Date: Sun, 12 Feb 2023 19:58:02 UTC

Severity: normal

Found in version 30.0.50

Fixed in version 30.1

Done: Ulrich Müller <ulm <at> gentoo.org>

Bug is archived. No further changes may be made.

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From: Michael Heerdegen <michael_heerdegen <at> web.de>
To: Ulrich Müller <ulm <at> gentoo.org>
Cc: 61460 <at> debbugs.gnu.org
Subject: bug#61460: 30.0.50; Calendar shows eclipse for quarter moon
Date: Mon, 13 Feb 2023 06:13:49 +0100

Michael Heerdegen <michael_heerdegen <at> web.de> writes:

> My questions: [...]

BTW (3), I also don't understand those conversions of the latitude:

#+begin_src emacs-lisp
(defun eclipse-check (moon-lat phase)
  (let* ((moon-lat (* (/ float-pi 180) moon-lat))
         (moon-lat (abs (- moon-lat (* (floor (/ moon-lat float-pi))
                                       float-pi))))
         (moon-lat (if (> moon-lat 0.37)
                       (- float-pi moon-lat)
                     moon-lat))
         (...))
    (...)))
#+end_src

What does this do?  Don't we just want to convert a value in [0 360) to
one in [-pi pi] and use the absolute value of that, or so?  That would
look like

  (abs (* (/ float-pi 180) (- moon-lat 180)))

Why is our calculation so complicated?


Michael.
This bug report was last modified 2 years and 88 days ago.

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