The Andromeda Galaxy, also known as M31, is an SB type spiral galaxy approximately 2.5 million light-years from Earth. It's one of the galaxies in our Local Group, which also contains the Milky Way, the Triangulum Galaxy, and other smaller galaxies. It's the closest galaxy to us, only dwarf galaxies that are orbiting around the Milky Way are at a smaller distance than the M31. The Andromeda Galaxy was formed roughly 10 billion years ago from the collision and subsequent merger of smaller protogalaxies. Similarly to the Milky Way, the Andromeda Galaxy also has satellite galaxies, consisting of 14 known dwarf galaxies. The best known and most observed satellite galaxies are M32 and M110.
It received its name from the area of the sky in where it appears, the constellation of Andromeda, which was named after the mythological princess Andromeda.
The Andromeda Galaxy is inexorably falling toward the Milky Way with a speed 402,000 kilometers per hour under the mutual pull of gravity between the two galaxies and the invisible dark matter that surrounds them both. But they are expected to collide in 4 billion years, and merge into a single elliptical galaxy.
In the year 964, the Persian astronomer Abd al-Rahman al-Sufi described the Andromeda Galaxy, in his Book of Fixed Stars as a "nebulous smear". In 1612, the German astronomer Simon Marius gave an early description of the Andromeda Galaxy based on telescopic observations. And in 1764, Charles Messier catalogued Andromeda as object M31.
The apparent magnitude of the Andromeda Galaxy, at 3.4, is among the brightest of the Messier objects, making it visible to the naked eye on moonless nights, even when viewed from light polluted areas.
INSTRUMENT Canon EF 70-200mm F/2.8 II
CAMERA Canon EOS 60Da
MOUNT Vixen Sphinx
GUIDING Lacerta MGen Autoguider
EXPOSURE TIME 121x5min iso 800
LOCATION Gyöngyös, Hungary
FILTER Astronomik CLS
