24. Photographic Astrometry

Abstract

The name of this commission was recently changed from “Parallaxes and Proper Motions”. These data are at this time indeed obtained mostly by the techniques of photographic astrometry, but so is the bulk of relative star positions. It is clear, however, that the nonabsolute determination of relative positions and data derived from them in narrow fields (which describes the scope of this Commission) is going to be carried out more and more also by nonphotographic methods, namely photoelectrically (Earth and satellite based) by interferometry (optical, radio, and speckle) and by direct imaging. This therefore creates considerable overlap with the subject areas and methods of a number of other Commissions, especially Commission 8, and it will be appropriate for Commission 24 in the near future to examine critically the overlapping areas of interest and to come to an agreement about the definition of the proper responsibilities of the individual commissions.