* The VSOP87D planetary theory (full and reduced precision) for Solar System ephemeris,
* Approximation to DE200 for the outer planets and Pluto, and
* Formulae from J. Meeus (1982) for Jovian and Saturnian natural satellites
* Model by the Bureau des Longitudes for Martian and Uranian natural satellites
* About 452 million stars from both the Tycho-2 Catalogue and a magnitude limited subset of the Guide Star Catalog II,
* About 1 million deep sky objects mainly from a subset of HYPERLEDA,
* About 288,000 minor planets and comets orbital elements from the IAU Minor Planet Center and Lowell Observatory (that can be updated),
and other specialized catalogs. It also include the Digital Lunar Orbiter Photographic Atlas of the Moon. XEphem is a client for Internet data sources such as the Digitized Sky Survey, Solar and Heliospheric Observatory, AAVSO light curves, and global temperature and cloud coverage. Through the Instrument Neutral Distributed Interface, XEphem can control some models of amateur telescopes, such as by Meade, Celestron, and Vixen, and auxiliary telescope components.
XEphem started as a Unix and Motif conversion of the IBM PC-based ephem. It was initially released in December 1993 with version 2.5. The most recent version is 3.7.5 (July 2011). XEphem's source code is available, but its free usage is restricted for personal and educational purposes only. The full set of catalogs is only distributed with a purchase of the commercial version.