Parallaxes and proper motions for 20 open clusters as based on the new Hipparcos catalogue
Parallaxes and proper motions for 20 open clusters as based on the new Hipparcos catalogue
A new reduction of the astrometric data as produced by the Hipparcos mission has been published, claiming that the accuracies for nearly all stars brighter than magnitude $\mathrm{Hp}=8$ are improved, by up to a factor 4, compared to the original catalogue. As correlations between the underlying abscissa residuals have also …