PPM Star Catalogue
In this article we will explore the fascinating world of PPM Star Catalogue, a topic that has captured the attention of people of all ages and from various parts of the world. In order to fully understand this phenomenon, we will delve into its history, origin and evolution over time. In addition, we will analyze its impact on society and how it has influenced different aspects of our daily lives. Through a multidisciplinary approach, we will examine the most relevant aspects related to PPM Star Catalogue, from its cultural manifestations to its importance in the scientific field, with the aim of providing a comprehensive vision of this exciting topic.
The PPM Star Catalogue (Positions and Proper Motions Star Catalogue) is the successor of the SAO Catalogue. It contains precise positions and proper motions of 378,910 stars on the whole sky in the J2000/FK5 coordinate system. It is designed to represent as closely as possible the IAU (1976) coordinate system on the sky, as defined by the FK5 star catalogue. Thus, the PPM is an extension of the FK5 system to higher star densities and fainter magnitudes. [1]
Description
The PPM can be considered a replacement of two preceding astrometric catalogs which served a similar purpose: AGK3 and the SAO Catalog. In contrast to the PPM, these older catalogs are based on (1) the now obsolete FK4 system of positions and proper motions, and (2) only two position measures per star.[2]
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. [2]
The data contained in the catalogue is downloadable from NASA (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 ISBN 978-3-86025-000-6
- ^ PPM – Positions and Proper Motions Catalog
- ^ a b "PPM Star Catalog". Harvard. Retrieved 2008-07-10.
External links
See also
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