A dwarf spheroidal galaxy (type dSph) in the Local Group of galaxies, discovered in 1994 in the constellation of Sagittarius and comparable in size with the Fornax Dwarf Galaxy. It has approximately 2.8 × 107 times the luminosity of the Sun, and is at least 10 000 l.y. across. The Sagittarius Dwarf lies about 65 000 l.y. from the centre of our Galaxy, and is the Galaxy’s closest known satellite. It is on the far side of the Galaxy as viewed from Earth, and is being elongated by strong tidal disruption as it merges with our Galaxy.