Variable stars are those that change brightness. Their variability may be due to geometric processes such as rotation, or eclipse by a companion star, or physical processes such as vibration, ﬂares, or cataclysmic explosions. In each case, variable stars provide unique information about the properties of stars, and the processes that go on within them.
The Local Group of Galaxies is the small, loose cluster to which our Milky Way
Galaxy belongs. It consists of approximately 36 known members, most of which are
dwarf galaxies. This Atlas includes identification charts for 32 members for which
identification atlases have not hitherto been published. There are numerous atlases of
various sorts for the Milky Way Galaxy and there is a published atlas for M31 and its
two close companions, M32 and NGC 205 (Hodge 1981). The Magellanic Clouds
have also been covered by identification atlases (Hodge and Wright 1967 and 1977).