La Mesure Des Vitesses Radiales Avec Un Prisme Objectif Associe A Un Telescope De Schmidt

Abstract Radial velocity measurements with an objective-prism mounted on a Schmidt telescope. A 62 cm diameter objective-prism is mounted on the CNRS-University of Liège Schmidt telescope at the Haute Provence Observatory. The field is 4 x 4° and the limiting magnitude is 12.5 on IllaJ hyper-sensitised plates. The dispersion is 200 A mm-1 at 4220 A. The plates are measured with a special machine and data are reduced by means of a computer with a correlation method. Stars of all spectral types are measured. The probable error is of some 4 km sec -1 over a mean of at least 3 plates. Already several lists of radial velocities of stars belonging to field situated at -30° of galactic latitude have been published. We have also started radial velocity observations for the Hipparcos Program.