Library of date/time manipulation routines for practical astronomy. Most of them are based on so called *Julian date (JD)*, which is the number of days elapsed since mean UT noon of January 1st 4713 BC. This system of time measurement is widely adopt...

Delta-T indicates the difference between *UT* and *TDT* (*Terrestrial Dynamic Time*), which used to be called *Ephemeris time* in the last century. While *UT* is not a uniform time scale (it is occasionally adjusted, due to irregularities in the Eart...

Sidereal time related calculations....

Library of astronomical calculations, based mainly on *"Astronomy On The Personal Computer"* by *O.Montenbruck* and *T.Phleger*, *Fourth Edition, Springer-Verlag, 2000*. There are many astronomical libraries available in the public domain. While givi...

Celestial sphera related calculations used by Astro::Montenbruck modules....

The times of he equinoxes and solstices are the instants when the apparent longiude of the Sun is a multiple of 90 degrees. Searches solstices and eqinoxes. Algorythms are based on *"Astronomical Formulae for Calculators"* by *Jean Meeus*, *Forth Edi...

Functions dealing with ecliptic obliquity....

High level interface for calculating rise, set and transit times of celestial bodies, as well as twilight of different types. There are two low-level functions for calculating the events, based on based on different algorithms: 1. Astro::Montenbruck:...

Searches lunar quarters. Algorythms are based on *"Astronomical Algorythms"* by *Jean Meeus*, *Second Edition*, *Willmann-Bell, Inc., 1998*....

Calculates apparent geocentric ecliptic coordinates of the Sun, the Moon, and the 8 planets. Algorithms are based on *"Astronomy on the Personal Computer"* by O.Montenbruck and Th.Pfleger. The results are supposed to be precise enough for amateur's p...

Helper functions for scripts, mainly string related....

Calculates perturbations for Sun, Moon and the 8 planets. Used internally by Astro::Montenbruck::Ephemeris module. EXPORT * pert(%args) * "addthe($a, $b, $c, $d)"...

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...

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...

Base class for a planet. Designed to be extended. Used internally in Astro::Montenbruck::Ephemeris modules. Subclasses must implement heliocentric method....

Child class of Astro::Montenbruck::Ephemeris::Planet, responsible for calculating Sun position....

Child class of Astro::Montenbruck::Ephemeris::Planet, responsible for calculating Moon position for the *mean equinox of date*. Formulae are based on analytical theory of by E.E.Brown (Improved Lunar Ephemeris) with accuracy of approx. 1 arc-second....

Child class of Astro::Montenbruck::Ephemeris::Planet, responsible for calculating Pluto position. The coordinates are first calculated relative to the fixed ecliptic of 1950, and then transformed to the equinox of date. This method is nesessary becau...