The HIPPARCOS Input Catalogue. III - Photometry

Abstract

Photometric information about stars proposed for observation by the astrometric satellite Hipparcos is used for several purposes. Instrumental colors and magnitudes served as an input to the definition of the observing program (e.g. in defining the magnitude-limited survey), in optimizing the observations by allocating observing time according to the star's magnitude and for the calibrations, on-orbit, of the satellite detection chains (main mission and Tycho). In cases where existing magnitudes data were inadequate or missing new ground-based observations were required. The work undertaken in the INCA consortium in this area is described here.