Astro:...:Sunset(3pm)

✨ NAME ✨

okay so bestie, this is the Astro:...:Sunset(3pm) page for Astro::Montenbruck::RiseSet::Sunset, from the User Contributed Perl Documentation manual — and it's literally all about rise and set. 💅

---

🌸 SYNOPSIS 🌸

like, here's the whole vibe in code, no cap:

use Astro::Montenbruck::MathUtils qw/frac/;
use Astro::Montenbruck::RiseSet::Constants qw/:events :altitudes/;
use Astro::Montenbruck::RiseSet::Sunset qw/:riseset_func/;

my $func = riseset_func(
    date     => [1989, 3, 23],
    phi    => 48.1,
    lambda => -11.6
);

$func->(
    get_position => sub {
        my $jd = shift;
        # return equatorial coordinates of the celestial body for the Julian Day.
    },
    sin_h0       => sin( deg2rad($H0_PLANET) ),
    on_event     => sub {
        my ($evt, $jd) = @_;
        say "$evt: $jd";
    },
    on_noevent   => sub {
        my $state = shift;
        say $state;
    }
);

🎀 VERSION 🎀

Version 0.01 — iconic. ✨

🦋 DESCRIPTION 🦋

these are low level routines for calculating rise and set times of celestial bodies. 🪐

💅 FUNCTIONS 💅

🍓 riseset_func ( %args ) 🍓

this is the time of rise and set events. ⏰

💖 Named Arguments 💖

• get_position — a function that, given the Standard Julian Day, returns the equatorial coordinates of the celestial body, in radians.
• date — array of year (astronomical, zero-based), month [1..12] and day, [1..31].
• phi — geographic latitude, degrees, positive northward.
• lambda — geographic longitude, degrees, positive westward.
• get_position — a function that, given the Standard Julian Day, returns the equatorial coordinates of the celestial body, in radians. yes bestie, it's listed twice in the original — keeping both, no cap 💀
• sin_h0 — sine of the standard altitude, i.e. the geometric altitude of the center of the body at the time of apparent rising or setting.
• on_event callback — called when the event time is determined. The arguments are:
  • event type, one of $EVT_RISE or $EVT_SET
  • Universal time of the event

on_event => sub { my ($evt, $ut) = @_; ... }

• on_noevent — called when the event does not happen at the given date, either because the body never rises, or is circumpolar. The argument is respectively $STATE_NEVER_RISES or $STATE_CIRCUMPOLAR.

on_noevent => sub { my $state = shift; ... }

👑 AUTHOR 👑

shoutout to the iconic author line: Sergey Krushinsky, "<krushi at cpan.org>" — periodt. 👑

🌈 COPYRIGHT AND LICENSE 🌈

Copyright (C) 2010-2022 by Sergey Krushinsky

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

💖 okay that's the whole page, bestie! source/version: Astro:...:Sunset(3pm); footer version: perl v5.42.2; date: 2026-02-15 — bye, love u, mwah! 💖