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.
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This article is an automated import of the Wikipedia article "PPM Star Catalogue", available at https://en.wikipedia.org/wiki/PPM_Star_Catalogue . Text is licensed under CC BY-SA 4.0.