XEphem
Encyclopedia
XEphem is a Motif
based ephemeris
and planetarium
program for Unix-like
operating systems developed by Elwood C. Downey.
XEphem uses
and includes
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 curve
s, 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.
Tycho-2 catalog can be generated from the original data. This is also possible for the non-stellar catalogs in the ASCII
XEphem can also read several astrometric
catalogs
in their original formats:
Motif (widget toolkit)
In computing, Motif refers to both a graphical user interface specification and the widget toolkit for building applications that follow that specification under the X Window System on Unix and other POSIX-compliant systems. It emerged in the 1980s as Unix workstations were on the rise, as a...
based ephemeris
Ephemeris
An ephemeris is a table of values that gives the positions of astronomical objects in the sky at a given time or times. Different kinds of ephemerides are used for astronomy and astrology...
and planetarium
Planetarium
A planetarium is a theatre built primarily for presenting educational and entertaining shows about astronomy and the night sky, or for training in celestial navigation...
program for Unix-like
Unix-like
A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....
operating systems developed by Elwood C. Downey.
XEphem uses
- The VSOP87D planetary theory (full and reduced precision) for Solar SystemSolar SystemThe Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
ephemeris, - Approximation to DE200 for the outer planetsOuter planetsThe outer planets are those planets in the Solar System beyond the asteroid belt, which typically refers to these gas giant planets in order of their distance from the Sun:...
and PlutoPlutoPluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...
, and - Formulae from J. Meeus (1982) for JovianJupiterJupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
and SaturnSaturnSaturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...
ian natural satelliteNatural satelliteA natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called its primary. The two terms are used synonymously for non-artificial satellites of planets, of dwarf planets, and of minor planets....
s - Model by the Bureau des LongitudesBureau des LongitudesThe Bureau des Longitudes is a French scientific institution, founded by decree of 25 June 1795 and charged with the improvement of nautical navigation, standardisation of time-keeping, geodesy and astronomical observation. During the 19th century, it was responsible for synchronizing clocks...
for MartianMarsMars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
and UranianUranusUranus is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. It is named after the ancient Greek deity of the sky Uranus , the father of Cronus and grandfather of Zeus...
natural satellites
and includes
- About 452 million stars from both the Tycho-2 CatalogueTycho-2 CatalogueThe Tycho-2 Catalogue is a catalogue of more than 2.5 million of the brightest stars.- Catalogue :The astrometric reference catalogue contain positions, proper motions, and two-color photometric data for the 2,539,913 of the brightest stars in the Milky Way, of which about 5000 are visible to the...
and a magnitudeApparent magnitudeThe apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
limited subset of the Guide Star Catalog II, - About 1 million deep sky objects mainly from a subset of HYPERLEDA,
- About 288,000 minor planetMinor planetAn asteroid group or minor-planet group is a population of minor planets that have a share broadly similar orbits. Members are generally unrelated to each other, unlike in an asteroid family, which often results from the break-up of a single asteroid...
s and cometCometA comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
s orbital elements from the IAUIAUIAU may refer to:*International Astronomical Union*International American University*International American University College of Medicine*International Association of Universities*International Association of Ultrarunners...
Minor Planet CenterMinor Planet CenterThe Minor Planet Center operates at the Smithsonian Astrophysical Observatory , which is part of the Center for Astrophysics along with the Harvard College Observatory ....
and Lowell ObservatoryLowell ObservatoryLowell Observatory is an astronomical observatory in Flagstaff, Arizona. Lowell Observatory was established in 1894, placing it among the oldest observatories in the United States, and was designated a National Historic Landmark in 1965....
(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
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
data sources such as the Digitized Sky Survey
Digitized Sky Survey
The Digitized Sky Survey is a digital version of several photographic atlases of the night sky, and an ongoing project to produce more digital versions of photographic astronomical datasets.- Versions and source material :...
, Solar and Heliospheric Observatory
Solar and Heliospheric Observatory
The Solar and Heliospheric Observatory is a spacecraft built by a European industrial consortium led by Matra Marconi Space that was launched on a Lockheed Martin Atlas IIAS launch vehicle on December 2, 1995 to study the Sun, and has discovered over 2100 comets. It began normal operations in May...
, AAVSO light curve
Light curve
In astronomy, a light curve is a graph of light intensity of a celestial object or region, as a function of time. The light is usually in a particular frequency interval or band...
s, and global temperature and cloud coverage. Through the Instrument Neutral Distributed Interface
Instrument Neutral Distributed Interface
INDI is a Distributed Control System protocol to enable control, data acquisition and exchange among hardware devices and software front ends, with particular focus on astronomical instrumentation.-Introduction:Elwood Downey started the INDI Protocol initiative in 2003 to develop a platform and...
, XEphem can control some models of amateur telescopes, such as by Meade, Celestron
Celestron
Celestron is a company that manufactures and imports telescopes, binoculars, spotting scopes, microscopes, and accessories for their products.-Origins and History:...
, and Vixen
Vixen (telescopes)
Vixen is a Japanese company that makes telescopes, binoculars, spotting scopes and accessories for their products.Among many other more mainstream products they have created two unusual varieties of catadioptric telescopes with an open tube design instead of the full-aperture corrector plate of the...
, and auxiliary telescope components.
XEphem started as a Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
and Motif conversion of the IBM PC
IBM PC
The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12, 1981...
-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.
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 binaryBinary file
A binary file is a computer file which may contain any type of data, encoded in binary form for computer storage and processing purposes; for example, computer document files containing formatted text...
Tycho-2 catalog can be generated from the original data. This is also possible for the non-stellar catalogs in the ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
.edb format, such as for HYPERLEDA.XEphem can also read several astrometric
Astrometry
Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...
catalogs
Astronomical catalog
An astronomical catalog or catalogue is a list or tabulation of astronomical objects, typically grouped together because they share a common type, morphology, origin, means of detection, or method of discovery...
in their original formats:
- GSC 1.2Guide Star CatalogThe Guide Star Catalog is also known as the Hubble Space Telescope, Guide Catalog . It is a star catalog compiled to support the Hubble Space Telescope with targeting off-axis stars. GSC-I contained approximately 20,000,000 stars with apparent magnitudes of 6 to 15. GSC-II contains 945,592,683...
and GSC-ACT - USNO A/SA 1.0/2.0
- UCAC2
See also
- Cartes du CielCartes du CielCartes du Ciel is a free planetarium program for Linux, Mac OS X and Windows. With the change to version 3, Linux has been added as a target platform, licensing has changed from freeware to GPL and the project moved to a new website....
- CelestiaCelestiaCelestia is a 3D astronomy program created by Chris Laurel. The program is based on the Hipparcos Catalogue and allows users to travel through an extensive universe, modeled after reality, at any speed, in any direction and at any time in history...
- Hallo Northern Sky (HN Sky)HNSKYHNSKY or Hallo Northern Sky is a freeware planetarium program for Microsoft Windows to simulate the night sky. It is provided with several non-English language modules, as well as several stellar databases....
- KStarsKStarsKStars is a planetarium program using the KDE Platform for Unix-like computer operating systems. It provides an accurate graphical representation of the night sky, from any location on Earth, at any date and time...
- Stellarium
- Universe SandboxUniverse SandboxUniverse Sandbox is an interactive space gravity simulator. Using Universe Sandbox, one can see the effects of gravity on objects in the universe and run scale simulations of our Solar System, various galaxies or other simulations, while at the same time, interacting and maintaining control over...