The parallax and astrometric orbit of Procyon have been redetermined from PDS measurements of over 250 photographic plates spanning 83 years, with roughly 600 exposures used in the solution. These data are combined with two modern measurements of the primaryÈwhite dwarf separation, one utilizing a ground-based coronagraph, the other, the Planetary Camera (PC) of the Hubble Space T elescope. Together with the redetermined astrometric orbit and parallax, these yield new estimates of the component masses. The derived masses are 1.497^0.037for the primary and for the M _ 0.602^0.015M _ white dwarf secondary. These mass values are heavily weighted by the PC separation measurement, which, while being somewhat discordant with the ground-based measures, we argue is more precise and more accurate and thus deserving of its greater weight. This stated, the long-standing discrepancy between previous determinations of the observed mass of Procyon A (1.75 and the value supported M _ ) by stellar evolution models (1.50 appears to be reconciled. M _ )

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Measures of 25 members of the Hyades and about 260 field stars have been made for parallax and proper motion in two ways, automatically using a PDS microdensitometer and manually using a conventional measuring machine. Reductions show the parallax errors from the former are about half those of the latter method.