The PPM Star Catalogue (Positions and Proper Motions Star Catalogue) is the successor of the

SAO Catalogue The Smithsonian Astrophysical Observatory Star Catalog is an astrometric star catalogue, created by Smithsonian Institution, a research institute. It was published by the Smithsonian Astrophysical Observatory in 1966 and contains 258,997 stars. T ...

. It contains precise positions and proper motions of 378,910

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

s on the whole sky in the

J2000 In astronomy, an epoch or reference epoch is a instant, moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a Astronomical object, celestial body, ...

FK5 The Catalogue of Fundamental Stars is a series of six astrometric catalogues of high precision positional data for a small selection of stars to define a celestial reference frame, which is a standard coordinate system for measuring positions of s ...

coordinate system. It is designed to represent as closely as possible the

IAU The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach ...

(1976) coordinate system on the sky, as defined by the

star catalogue A star catalogue is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different star catalogues which have been produced for different purposes over the years, ...

. Thus, the PPM is an extension of the FK5 system to higher star densities and fainter magnitudes. PPM – Positions and Proper Motions Catalog
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Description

The PPM can be considered a replacement of two preceding

astrometric Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way. Histor ...

catalogs which served a similar purpose:

AGK3 The ''Astronomische Gesellschaft Katalog'' (AGK) is an astrometric star catalogue. Compilation for the first version, AGK1, was started in 1861 by Friedrich Argelander and published between 1890 and 1954, listing 200 000 stars down to ninth m ...

and the SAO Catalog. In contrast to the PPM, these older catalogs are based on (1) the now obsolete

FK4 The Catalogue of Fundamental Stars is a series of six astrometric catalogues of high precision positional data for a small selection of stars to define a celestial reference frame, which is a standard coordinate system for measuring positions of s ...

system of positions and proper motions, and (2) only two position measures per star. While the SAO catalog is more or less complete to V=9, with 4,503 stars fainter than V=10, the PPM catalog is fairly complete to V=9.5, with 102,672 stars fainter than V=10 and 22,395 stars fainter than V=11. Released after the original PPM, the PPM supplemental list was intended to render the PPM complete to magnitude V=7.5. For fainter magnitudes, the supplemental list documentation states that, ''... of the perhaps 20,000 stars between V=7.5 and V=8.5 only a few hundred are missing from PPM. So, the combined PPM can be considered as practically complete to at least V=8.5. In photographic magnitudes this corresponds to roughly 9 mag. '' The data contained in the catalogue is

downloadable In computer networks, download means to ''receive'' data from a remote system, typically a server such as a web server, an FTP server, an email server, or other similar system. This contrasts with uploading, where data is ''sent to'' a remote s ...

from

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

(and other sites). The four files of the catalog are ''PPM North'', ''PPM South'', ''Bright Star Supplement to PPM'', and ''The 90000 stars Supplement to the PPM Catalogue''.

References

* Roeser, S., Bastian, U., 1991, Astronomisches Rechen-Institut, Heidelberg, Vols. I and II, printed by Spektrum Akademischer Verlag, Heidelberg

External links

The Guide Star Catalog v1.2Star catalogues

Description

References

External links

See also