Vital Statistics

Description AEPHEM is an astronomical ephemeris and reduction library.
Language C
Current Release canopus (January 2013)
Licence GPL
Adam Hincks (


AEPHEM is an astronomical ephemeris and reduction C library, along with python bindings. Orbital information can be taken from built-in perturbation tables for major Solar System objects, JPL ephemerides (which need to be downloaded seperately) and Keplerian orbital elements.

Routines allow for reduction to geocentric and topocentric equatorial coordinates and can correct for: precession, annual and diurnal aberration, annual and diurnal parallax, nutation, light travel time, light deflection and atmospheric refraction (in both optical and millimetre/sub-millimetre). Sub-observer points can also be calculated.

Calendar routines allow for conversion between calendar time, UNIX time, sidereal time and Julian Dates, and offsets between Universal Coordinated Time (UTC), Universal Time (UT1) and Terrestrial Time (TT) are readily calculated.

Routines for transforming from equitorial to horizonal and galactic coordinates are also provided.

AEPHEM is based on AA, by Stephen L. Moshier, available at Most algorithms are taken from the Astronomical Almanac, and references for each function are provided in these help pages. The functions for parsing JPL ephemerides are based on the software library.

APHEM is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.