ASSOCIATIONS BETWEEN THE ANCIENT STAR CATALOGUES

There are just two substantial sources of star coordinates preserved for us from antiquity: the star catalogue of Ptolemy’s Almagest1, and the rising, setting, and culmination phenomena, along with some star declinations and right ascensions, from Hipparchus’ Commentary to Aratus2. Given the controversy associated with the idea that Ptolemy’s catalogue is, in whole or in substantial part, a copy of an earlier but now lost catalogue of Hipparchus, it is of interest to try and establish clear and significant associations, or the lack thereof, between the two sets of ancient star data. There have been two complementary efforts to clarify the possible associations. Vogt3 used the phenomena and declinations to reconstruct the ecliptical coordinates of some 122 stars in Hipparchus ’ Commentary that also appear in the Almagest catalogue. Vogt’s conclusion was that since his reconstructed coordinates and the Almagest coordinates were, in general, different, Ptolemy did not obtain his data from Hipparchus. Vogt did notice five stars with very similar errors and concluded that Ptolemy probably did copy those from Hipparchus. More recently, however, Grasshoff4 has pointed out that there are several reasons to doubt Vogt’s conclusion. Further, Grasshoff worked in the opposit