The site of the Hipparcos mission (in french)
The measurement of distance is one of the keys to unlocking our view of the World around us and of the Universe, and also, indirectly, our understanding of the physical processes underlying stellar and galactic evolution.
The European Hipparcos satellite has observed the sky for four years, from November 1989 to March 1993. Managed by the European Space Agency, it has enabled the determination of the positions, the trignometric parallaxes (thus the distances) and the proper motions (motions along the celestial sphere) of 118 000 stars of every type, and of about fifty solar system bodies.
site Hipparcos