Wide pairs in the Washington Double Star Catalogue (WDS)

Summary TheCatalog of Observations, maintained at the U.S. Naval Observatory as an integral part of theWashington Double Star Catalog, is fast becoming a complete data base with the continued accession of the older data. For the wide pairs contained therein, the principal interest is whether or not they are physical. This report describes the observational history of various series of older observations, and points out what needs to be done to provide a reliable judgement as to the physical relationship of such pairs. An expanded version of this paper will be presented at theIAU Colloquium 100 ‘Fundamentals of Astrometry’ in Belgrade, 8–11 September, 1987.