Determination of highly accurate proper motions for 32 Hipparcos stars from photographic plates.

Abstract

The authors have reduced 70 exposures on 32 photographic plates taken in four sky areas around the radio source 0316+413, the galaxy NGC 7302, the Pleiades astrometric standard region, and some other objects. The plates were obtained with the 40-cm astrographic refractor at the SheShan(Zô-Sé) station of the Shanghai Observatory. Using the PPM catalog as the initial reference catalog and the central overlapping method with the iteration process, the authors have obtained highly accurate positions and proper motions for 32 Hipparcos stars. Due to the large epoch differences (up to 86 years), the mean internal errors of proper motions for 32 stars are 0.59 mas/yr and 0.53 mas/yr in right ascension and declination, while those of positions are 23 mas and 18 mas, respectively. Their results and those of other catalogs were compared.