Astron. Astrophys. 335, L65-L68 (1998)

Letter to the Editor

The Tycho Reference Catalogue ^*

E. Hog ¹, A. Kuzmin ², U. Bastian ³, C. Fabricius ¹, K. Kuimov ², L. Lindegren ⁴, V.V. Makarov ¹, and S. Röser <sup>3

1</sup> Copenhagen University Observatory, Juliane Maries Vej 30, DK-2100 Copenhagen O, Denmark
² Sternberg Astronomical Institute, Universitetsky prosp. 13, 119899 Moscow, Russia
³ Astronomisches Rechen-Institut, Mönchhofstrasse 12-14, D-69120 Heidelberg, Germany
⁴ Lund Observatory, Box 43, S-22100 Lund, Sweden

Received 6 April 1998 / Accepted 19 May 1998

Abstract

The Tycho Reference Catalogue (TRC) contains high-quality positions and proper motions for stars of the Tycho Catalogue. The proper motions were derived from Tycho positions and Astrographic Catalogue positions reduced to the Hipparcos system. The median accuracy of the TRC position components is 40 mas at J1991.25. The median precision of the proper motion is about 2.5 mas/yr . Systematic errors are less than about 1.0 mas(/yr). The quality of the proper motions in TRC is assessed by comparison with the Hipparcos and Tycho Catalogues. Comparison with the recent ACT Catalogue which is based on an independent reduction of the same observations as used for the TRC is reported.

Key words: astrometry reference catalogues proper motions Astrographic Catalogue Tycho Catalogue

* Based on observations made with the ESA Hipparcos astrometry satellite, and on work by the Tycho Consortium in collaboration with the INCA, FAST and NDAC Consortia.

Send offprint requests to: E. Hog

© European Southern Observatory (ESO) 1998

Online publication: June 26, 1998

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