Astronomy and Astrophysics were first treated in volume III of the 6th edition of Landolt-Börnstein in 1952, then in volumes VI/1 and VI/2 of the New Series, 1965 and 1981/82 respectively. The present volume VI/3 is a further supplementation of volume VI/1. The decimal classification scheme of the first supplement volumes, VI/2, has been maintained, fields without significant new developments are clearly indicated. A synoptic list of contents over all three volumes provides an excellent overview for the user as well as a Comprehensive Index in the forthcoming last subvolume of VI/3.