DateTime::Util::Astro::Common - Common Utilities For Astronomical Calendar Calculations
use DateTime::Util::Astro::Common qw( aberration dt_from_dynamical dynamical_moment_from_dt ephemeris_correction equation_of_time julian_centuries local_from_apparent nutation obliquity standard_from_local standard_from_universal universal_from_local universal_from_standard SPRING SUMMER AUTUMN WINTER MEAN_TROPICAL_YEAR RD_MOMENT_1900_JAN_1 RD_MOMENT_1810_JAN_1 RD_MOMENT_J2000 ); my $location = DateTime::Util::Astro::Location->new( longitude => $longitude, latitude => $latitude, zone => $zone, elevation => $elevation );
DateTime::Util::Astro::Location implements some functions that are commonly used for astronomical calculations. As with other DateTime::Util::Astro:: modules this module only implements the bare minimum required to make astronomical calendars.
Calculates the effect of the sun's moving during the time its light takes takes to reach the Earth
The number and fraction of uniform-length centuries at a given moment.
Calculates the offset from "dynamical time", which is caused by the retarding effects of tide and other atmospheric conditions.
These are used to calculate the ephemeris_correction.
Calculates the difference between "apparent midnight" and the "mean midnight"
Calculates the fractional number of centuries since January 1, 2000 (Gregorian).
Calculates the effect caused by the wobble of the Earth.
Calculates the inclination of th Earth
The solar longitude for equinoxes and solstices.
The time it takes for the mean sun to return to the same position relative to the celestial equator
DateTime::Util::Astro::Location probably isn't worth existing, as I believe the math involved with locations can probably be done via DateTime itself, or at least via DateTime::Locale and DateTime::TimeZone objects.
Hence it is foraseeable that DateTime::Util::Astro::Location will be phased out eventually and I've opted to keep it as a private class within his module, so that it doesn't pollute users' file systems.
Copyright (c) 2004-2007 Daisuke Maki <email@example.com>
 Edward M. Reingold, Nachum Dershowitz "Calendrical Calculations (Millenium Edition)", 2nd ed. Cambridge University Press, Cambridge, UK 2002