The HIPPARCOS astrometric satellite and visual double stars

Abstract

Astrometry from the Earth, in the past as well as at present, is described with particular attention to the evolution of the observational techniques from the last century to date and to the consequent improvement of results obtained by continually improved techniques. The scientific goals of the Hipparcos mission, the first astrometric space mission in history, are then considered. After a detailed analysis of the mission's technical and scientific features, a historical outline is provided which includes a description of the various steps as well as unhappy events that affected the existence of Hipparcos from its launch until now. The mission's expected results are then considered and the astrometric goals concerning the double and multiple star systems described. The Astronomical Observatory of Turin is directly involved in the analysis of the data and results provided by Hipparcos. Finally, the scientific as well as astrodynamic return of the mission is discussed.