A catalogue of positions and proper motions of stars, generally brighter than about magnitude 9, derived mostly from meridian observations made over many decades, which defines an accurate stellar reference frame. Apart from the German series (see fk), other fundamental catalogues, produced in the USA, are the Preliminary General Catalogue (PGC; 6188 stars; L. Boss, 1910), the General Catalogue (GC; 33 342 stars; B. Boss, 1937), and the N30 (5268 stars; H. R. Morgan, 1952). See also Boss General Catalogue.