XEphem

XEphem

Screenshot of the XEphem 3.7.2 with the Earth and sky views
Developer(s)	Elwood C. Downey
Stable release	3.7.5 / 25 July 2011
Operating system	Unix-like
Type	Amateur astronomy/observational astronomy
License	Proprietary
Website	[1]

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

XEphem uses

• The VSOP87D planetary theory (full and reduced precision) for Solar System ephemeris,
• Approximation to DE200 ^[1] for the outer planets and Pluto, and
• Formulae from J. Meeus (1982)^[2] 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.^[3] 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.

Contents 1 Catalogs 2 See also 3 References 4 External links

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.^[4] This is also possible for the non-stellar catalogs in the ASCII .edb format, such as for HYPERLEDA.^[5]

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

• GSC 1.2^[6] and GSC-ACT ^[7]
• USNO A/SA 1.0/2.0^[8]
• UCAC2 ^[9]

See also

• Cartes du Ciel
• Celestia
• Hallo Northern Sky (HN Sky)
• KStars
• Stellarium
• Universe Sandbox

References

1. ^ J. Chapront, Astron. Astrophys. Suppl. 109, 181 (1995).
2. ^ J. Meeus, Astronomical Formulae for Calculators (Willmann-Bell, Richmond, VA, 1982).
3. ^ Digital Lunar Orbiter Photographic Atlas of the Moon
4. ^ see e.g. Programs to generate XEphem 3.4 xe2 catalogs
5. ^ CDS VizieR HYPERLEDA
6. ^ CDS VizieR Guide Star Catalog
7. ^ CDS VizieR GSC-ACT
8. ^ USNO PMM catalogs
9. ^ CDS VizieR UCAC2

External links

• Official website
• Programs to generate XEphem 3.4 xe2 catalogs