The Double Star Section of the Société Astronomique de France has been in existence since 1980. It has set up observing groups covering various areas: close binaries, photographic measurements, re-observation of neglected pairs, and astrolabe measurements. All this has been thanks to our sceintific advisors, professionals specializing in double stars: Muller, Couteau, Soulié, Bacchus, and Dommanget. The Section meets twice a year, and it was at Lille in 1984 that J. Dommanget suggested that we should collaborate in the programme of identifying doubtful doubles for the input catalogue for the future satellite Hipparcos.

The first observations were made after the meeting in November 1984, from Paris and with amateur equipment, thanks to an initial list prepared by Prof. Bacchus. After several months we could tell that our equipment was insufficient, and that photocopies of the Palomar Sky Survey were not accurate enough. We needed more powerful instruments and a different organisation to resolve the ambiguity in identification that can arise by two close stars being confused and given the same coordinates, by the presence of a cluster, or by the existence of a faint star that is not given in the catalogues. In all these cases, identifying the star means being able to give it a designation, allowing it to be found on an atlas, and obtaining better coordinates so that the ambiguity is removed. It is a question of astrometry.