THE HIPPARCOS SOLAR-SYSTEM OBJECTS CATALOGS

Astrometric and photometric measurements of a number of solar system o bjects were performed by the Hipparcos satellite in both the Hipparcos main mission and the Tycho experiment. The results concern mainly ast eroids but also the planetary satellites Europa, Ganymede, Callisto, T itan and Iapetus, and the major planets Uranus and Neptune. The specif ic aspects of the Tycho/Hipparcos observations and reduction process i mplemented for the solar system objects are presented. Special attenti on is paid to the error budget of the reduction which is accurate to t he mas (milliarcsecond) level for the Hipparcos main mission. The cont ents of the Hipparcos and Tycho Solar System Objects Catalogues are br iefly described. Comparison between the results derived from the two C onsortia FAST and NDAC, as well as comparisons with ground-based obser vations, are given.