The Tycho-2 Catalogue of the 2.5 million brightest stars

E. Høg, C. Fabricius, V. V. Makarov, S. Urban, T. Corbin, G. Wycoff, U. Bastian, P. Schwekendick, A. Wicenec

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2157 Citations (Scopus)


The Tycho-2 Catalogue presented here is an astro-metric reference catalogue containing positions and proper motions as well as two-colour photometric data for the 2.5 million brightest stars in the sky. The Tycho-2 positions and magnitudes are based on precisely the same observations as the original Tycho Catalogue (hereafter Tycho-1) collected by the star mapper of the ESA Hipparcos satellite, but Tycho-2 is much bigger and slightly more precise, owing to a more advanced reduction technique. Components of double stars with separations down to 0.8 arcsec are included. Proper motions precise to about 2.5 mas/yr are given as derived from a comparison with the Astrographic Catalogue and 143 other ground-based astrometric catalogues, all reduced to the Hipparcos celestial coordinate system. Tycho-2 supersedes in most applications Tycho-1, as well as the ACT and TRC catalogues based on Tycho-1.

Original languageEnglish
Pages (from-to)L27-L30
JournalAstronomy and Astrophysics
Issue number1
Publication statusPublished - 2000
Externally publishedYes


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