M31 - NGC 224 - The Andromeda Galaxy

Messier 31 (M31) is a spiral galaxy in the constellation Andromeda. It is the nearest major galaxy outside our own Milky Way and the largest one in our Local Group. M31 is located about 2.5 million light years from earth and is approximately 220,000 light years in diameter. It has 14 known dwarf galaxies which are satellites. These dwarf galaxies include M32 and M110, both of which are easily seen in most images of the Andromeda Galaxy. Since it is visible to the naked eye, it is unknown who discovered it. It was described in the "Book of Fixed Stars" in 964 as a small cloud and as late as 1863 was still considered just a gaseous nebula. It wasn't until 1925 that it could be documented M31 was a separate galaxy outside our own.

Location Data Constellation: Andromeda Right ascension: 00h 42m 44s Declination: +41° 16′ 9″ Distance:  2,500,000 ly Size:  220,000 ly Observation Data Apparent magnitude: 3.40 App size: 178x63 arcmins (3°x1°)