A-stereoscopic view of our galaxy

The difficult but fundamental task of measuring stellar distances and space motions has preoccupied astronomers for centuries. The possibility of carr ying out these measurements form space, above the perturbing effects of the Earth's atmosphere, became reality with the launch of the European Space A gency's Hipparcos satellite in 1989. The resulting data became available to the astronomical community through the publications of the Hipparcos and T ycho Catalogues in 1997, providing a three-dimensional stellar census for s tars within a few hundred light years of Sun. The lecture explored various fields of astronomy which have been affected by the advent of milliarcsec a strometry.