Proper Motions in Praesepe

High-precision proper motions for 257 and 296 stars in a 90'x90' region centered on BD+20 2170 were obtained from seven plates taken with the Zo-se 40cm refractor (f=6895mm) in March, 1986 (see the "Plate Summary" section below), combined with six AC plates and the stellar positions in Russell's (1976, Ph.D. Thesis, Pittsburgh University). Combined with other data, membership probabilities were estimated by an improved maximum likelihood method.

A very good sample of 198 members is obtained with proper motion accuracies ranging from +/-0.2 to +/-5.0mas/yr, of which 60% are better than +/-1.0mas/yr; the completeness limit is about B=15.5mag. Note that the table published in electronic form associated to the paper published in 1995A&AS..113..419W presented positions not correctly associated to the stars (see the "History" section below)