New memberships, mean parallaxes and proper motions of all 9 open clusters
closer than 300 pc (except the Hyades) and 9 rich clusters between 300 and 500
pc have been computed using Hipparcos data. Precisions, ranging from 0.2 to 0.5
mas for parallaxes and 0.1 to 0.5 mas/yr for proper motions, are of great
interest for calibrating photometric parallaxes as well as for kinematical
studies. Careful investigations of possible biases have been performed and no
evidence of significant systematic errors on the mean cluster parallaxes has
been found. The distances and proper motions of 32 more distant clusters, which
may be used statistically, are also indicated.Comment: 15 pages, A&A in pres