Washington Double Star Catalog
Encyclopedia
The Washington Double Star Catalog, or WDS, is a catalog of double star
s, maintained at the United States Naval Observatory
. The catalog contains positions, magnitude
s, proper motion
s and spectral type
s and has entries for (as of July 2006) 102,387 pairs of double stars. The catalog also includes multiple star
s. In general, a multiple star with n components will be represented by entries in the catalog for n-1 pairs of stars.
, where it was used to construct the Index Catalog of Visual Double Stars, published in 1963. In 1965, under the initiative of Charles Worley, it was transferred to the Naval Observatory. It has since been augmented by a large number of measurements, from Hipparcos and Tycho
, speckle interferometry, and other sources.
Double star
In observational astronomy, a double star is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope. This can happen either because the pair forms a binary star, i.e...
s, maintained at the United States Naval Observatory
United States Naval Observatory
The United States Naval Observatory is one of the oldest scientific agencies in the United States, with a primary mission to produce Positioning, Navigation, and Timing for the U.S. Navy and the U.S. Department of Defense...
. The catalog contains positions, magnitude
Apparent magnitude
The 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...
s, proper motion
Proper motion
The proper motion of a star is its angular change in position over time as seen from the center of mass of the solar system. It is measured in seconds of arc per year, arcsec/yr, where 3600 arcseconds equal one degree. This contrasts with radial velocity, which is the time rate of change in...
s and spectral type
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
s and has entries for (as of July 2006) 102,387 pairs of double stars. The catalog also includes multiple star
Multiple star
A multiple star consists of three or more stars which appear from the Earth to be close to one another in the sky. This may result from the stars being physically close and gravitationally bound to each other, in which case it is physical, or this closeness may be merely apparent, in which case...
s. In general, a multiple star with n components will be represented by entries in the catalog for n-1 pairs of stars.
History
The database used to construct the WDS originated at Lick ObservatoryLick Observatory
The Lick Observatory is an astronomical observatory, owned and operated by the University of California. It is situated on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, USA...
, where it was used to construct the Index Catalog of Visual Double Stars, published in 1963. In 1965, under the initiative of Charles Worley, it was transferred to the Naval Observatory. It has since been augmented by a large number of measurements, from Hipparcos and Tycho
Hipparcos
Hipparcos was a scientific mission of the European Space Agency , launched in 1989 and operated between 1989 and 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky...
, speckle interferometry, and other sources.
External links
- The WDS at the US Naval Observatory
- The Washington Double Star Catalog at VizieRVizieRThe VizieR Catalogue Service is an astronomical catalog service provided by Centre de données astronomiques de Strasbourg.The origin of the ViZieR Catalogue Service dates back to 1993 as the ESA European Space Information System Catalogue Browser...