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G. Wallerstein (University of washington)
From as early as the beginning of the 20th Century the distance modulus of the Hyades was estimated to be near 3.00 magnitudes. The basis was proper motions derived from meridian circle observations and rather accurate radial velocities. In 1966 Paul Hodge and I suggested that it be revised upward by about 0.4 magnitudes. The reasons for this were three-fold: 1- dynamical parallaxes, 2- trigonometric prallaxes, and 3- the absolute magnitudes of the red giants as derived from the Wilson-Bappu relation. Between then and now some 50 papers have been published with new estimates of the distance. The most recent of these, by Perryman et al., uses proper motions derived from the Hipparcos satellite and very accurate radial velocities. Their derived distance modulus is 3.33 magnitudes. Their value will probably be considered to be definitive for many years to come. In my talk I will discuss a few of the determinations and relate the distance problem to that of the masses of the Hyades binaries and their chemical composition