Comparison of the GPM proper motions with the data from modern astrometric catalogues

Abstract

Proper motions, positions, B, V magnitudes and (B-V) colors from the GPM catalogue were compared with those from the Lick NPM1, the Carlsberg CMC, and the ESA "Tycho-2" catalogues. It turned out that the systematic differences of proper motions were in the range from 2 to 4 mas/yr. The external data also proved that the accuracy of the GPM proper motions is on average about 9 mas/yr, i. e., a factor of 1.1 less accurate than internally determined.