NAME

Astro::Montenbruck::RiseSet::Sunset — rise and set.

SYNOPSIS

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

riseset(
    date     => [1989, 3, 23],
    phi    => 48.1,
    lambda => -11.6,
    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, $ut) = @_;
        say "$evt: $ut";
    },
    on_noevent   => sub {
        my $state = shift;
        say $state;
    }
);

VERSION

Version 0.01

DESCRIPTION

Low level routines for calculating rise and set times of celestial bodies. Unlike Astro::Montenbruck::RiseSet::RST module, they are based on algorithms from the Montenbruck & Phleger book. They are especially usefull for calculating different types of twilight. Meeus's method is unsuitable for calculating astronomical twilight.

FUNCTIONS

riseset ( %args )

time of rise and set events.

Named Arguments

• get_position — function, which given Standard Julian Day, returns 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 — function, which given Standard Julian Day, returns equatorial coordinates of the celestial body, in radians.

• 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 is called when the event time is determined. The arguments are:

  • event type, one of $EVT_RISE or $EVT_SET

  • Univerrsal time of the event

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

• on_noevent is 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

Sergey Krushinsky, <krushi at cpan.org>

COPYRIGHT AND LICENSE

Copyright (C) 2010-2020 by Sergey Krushinsky

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