Tycho data analysis. Overview of the adopted reduction software and first results

Abstract

In the Tycho project astrometric and photometric data of about 1 000 000 stars to a limit of B=12 mag will be derived. The brightest 500 000 stars will obtain magnitudes in two colours B T and V T , the fainter 500 000 usually only one broad-band magnitude T. There is confidence that an accuracy will be achieved about 0.03 arcsec for positions and 0.03 mag for magnitudes, at B=10.5 mag. The results are obtained by appropriate treatment of the continuous data records generated by the Hipparcos satellite's star mapper (which provide simultaneous measurements in two spectral channels), based on predicted star transits using its own Tycho Input Catalogue.