Time-Keeper-Sky

The sky from a place: the sun, the moon, the planets and the bright stars, where each
is at an instant and when it rises, sets and crosses the meridian on a civil day;
twilight, the moon's phases, the seasons, the constellations, lunar and solar
eclipses, and what is up tonight. Every moment is a Time::Keeper value in the place's
time zone.

This distribution was Time-Keeper-Sun. It contains Time::Keeper::Sun and
Time::Keeper::Moon, which work as they did in Time-Keeper-Sun 0.02;
Time::Keeper::Sky is the observer, and a Time::Keeper::Sun is one.

    use Time::Keeper::Sky;

    my $sky = Time::Keeper::Sky->new(place => 'Europe/London');
    print $sky->on(year => 2026, month => 10, day => 15)->sunrise, "\n";
                                            # 2026-10-15T07:24:22+01:00

    my $now = Time::Keeper->now;
    my $j = $sky->position('jupiter', $now);   # altitude, azimuth, magnitude, ...
    my $d = $sky->on($now, 'Sirius');          # its rise, transit and set today

    for my $r ($sky->tonight) {
        printf "%-10s best at %s, %2.0f degrees up\n", $r->{body}, $r->{best}, $r->{altitude};
    }

    use Time::Keeper::Eclipse;
    my $e = Time::Keeper::Eclipse->next(kind => 'solar', after => $now, place => $sky);

The modules:

    Time::Keeper::Sky       the observer; the sun; any body by name; tonight
    Time::Keeper::Sun       the same, under its old name
    Time::Keeper::Moon      the phases, the moon's place and disc, its days
    Time::Keeper::Planet    Mercury to Neptune by the full VSOP87D, and Pluto
    Time::Keeper::Star      the 9,096 stars of the Yale Bright Star Catalogue
    Time::Keeper::Eclipse   lunar and solar eclipses, and one place's view

The astronomy is Meeus's, with VSOP87D for the planets and the rigorous model of the
Astronomical Almanac for the stars, all in C, with the tables compiled in: nothing is
read at run time and nothing outside Time::Keeper is needed. The results are measured
against the U.S. Naval Observatory, JPL's DE421 ephemeris, IMCCE and NASA's Five
Millennium Canons of eclipses, and the POD of each module says how close they come.

INSTALLATION

Time::Keeper must be installed first: this distribution is configured against the C
header it installs. Then:

    perl Makefile.PL
    make
    make test
    make install

SUPPORT AND DOCUMENTATION

After installing, you can find documentation for each module with the perldoc
command, starting with:

    perldoc Time::Keeper::Sky

LICENSE AND COPYRIGHT

This software is Copyright (c) 2026 by LNATION.

This is free software, licensed under:

  The Artistic License 2.0 (GPL Compatible)

The tables it compiles in come from the sources Time::Keeper::Sky's SOURCES section
names, with their terms.