An early TYCHO astrometric catalogue

Abstract

The TICR catalogue is arevision of TIC, theTYCHO Input Catalogue, and will contain positions derived from the first 12 months of TYCHO observations. Its properties, its role in TYCHO data analysis, and other possible uses are discussed. Since TICR will list about 500 000 stars with a positional precision of 0."15 (rms) and since it should become available early, it could be published two years after launch, during the mission. Preferably, proper motions should be included based on TICR and older ground-based first epoch positions, thus obtaining a precision about 0.003 ″/year for the stars in the northern sky, but decreasing to 0.010 "/year in some parts of the southern celestial hemisphere.