The Hipparcos mission and the RE-Reduction of Belgrade
zenith-telescope observations
           G. Damljanovic
Astrnomical Observatory, Volgina 7, 11050 Belgrade, Yugoslavia


   We prepared the results of the observations with Belgrade made in the
period 1949-1985 in a computer-readable form in order to make the
reduction in the FK5 reference frame. After the XXI IAU General
Assembly, Buenos Aires 1991, our investigation was in accordance with
the task of Commission 19  of the IAU Rotation of the Earth. The working Group
on Earth Rotation  in the HIPPARCOS reference frame. WG ERHRF was
formed to collect data of past optical astrometric observations. Some
results of our re-reduction are presented here.