HIPPARCOS, launched by Ariane-4 in 1989, gave astronomers a three-dimensional picture of the bright stars in our Universe for the
very first time. For four years, it scanned the sky, measuring the angles between stars. Hipparcos recorded, with an accuracy 100 times better than ever achieved before, the position and absolute magnitude of 120,000 stars. Its data is now available to scientists in a unique Catalogue.
