Suvarna Garge (Editor)

XEphem

Updated on
Edit
Like
Comment
Share on FacebookTweet on TwitterShare on LinkedInShare on Reddit
Developer(s)
  
Elwood C. Downey

Operating system
  
Unix-like

XEphem

Initial release
  
1990; 27 years ago (1990)

Stable release
  
3.7.6 / January 2013; 4 years ago (2013-01)

Preview release
  
3.7.7-RC5 / December 2014; 2 years ago (2014-12)

Type
  
Amateur astronomy/observational astronomy

XEphem is a Motif based ephemeris and planetarium program for Unix-like operating systems developed by Elwood C. Downey.

Contents

History

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 stable version is 3.7.6 (2013). 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.

Algorithms and models

XEphem uses

  • 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

    • and includes

  • 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.

    Catalogs

    While the free version of XEphem only includes a subset of the SKYMAP Master Catalog and the Messier Catalog, the internal format of the remaining catalogs can be inferred from the source code, and e.g. the internal binary Tycho-2 catalog can be generated from the original data. This is also possible for the non-stellar catalogs in the ASCII .edb format, such as for HYPERLEDA.

    XEphem can also read several astrometric catalogs in their original formats:

  • GSC 1.2 and GSC-ACT
  • USNO A/SA 1.0/2.0
  • UCAC2

    • Numerical routines are used in PyEphem with permission of Elwood Downey.

    References

    XEphem Wikipedia
    (Text) CC BY-SA