Andromeda, one of the 88 constellations

Andromeda is one of the 88 constellations in the whole day, located below Ursa Major and near Pegasus. Constellation position

In order to successfully find the Andromeda nebula among many stars, we need to be familiar with the autumn starry sky first. In autumn night, the Milky Way has turned to the northeast, and Cassiopeia can be seen swimming in the Milky Way. It has five bright stars, arranged in the shape of the English letter "W", which is easy to identify. To the west of Cassiopeia is Cepheus and to the east is Perseus. Not far from the south of the Milky Way, there are four bright stars arranged in an obvious quadrilateral, which is the famous autumn quadrilateral. All three stars in the quadrilateral belong to Pegasus, and only the star in the northeast corner is Andromeda A star. The visual magnitude of Andromeda A is level 2, white. Andromeda is about north 12, and there is a third-class binary star about 5 east. It is Andromeda gamma star, and its Chinese name is General Tian. We should pay special attention to this "heavenly general". The Andromeda nebula M3 1 is very close to it, just to the west 1.

The Andromeda Nebula has a total magnitude of 4 and an average brightness of 6 per unit area. On a clear moonless night, it is faintly visible to the naked eye, like a small white cloud. Its soft silvery white oval shape can be seen through a small astronomical telescope. Andromeda nebula is a typical spiral galaxy, but because it faces us sideways, it is not easy to see its spiral arms. Through a larger telescope, we can see some of its structures, for example, its core is particularly bright, and the brighter it gets toward the center, we can also see some spiral arms, black dust lines, globular clusters and star clouds. In addition, we can also see its two dwarf companion stars, one is a small, round and dense elliptical galaxy M32 in the south of M3 1, and the other is an elliptical galaxy M 1 10, which is slightly darker but larger and longer than M32 and located in the northwest of M3 1. There are also many dim stars in the Milky Way that fill this sky area, adding fascinating colors to the Andromeda Nebula.

Andromeda has a main galaxy, M3 1 (Andromeda), [2] which is one of the largest members of this galaxy group. Andromeda is characterized by two curves starting from Alpha, and you can easily find it from the connection between Cassiopeia and Polaris. Undoubtedly, the most famous galaxy in Andromeda is M3 1, which is an extragalactic galaxy and a galaxy as huge as the Milky Way. M3 1 is about 2 million light years away, and it is the farthest celestial body visible to the naked eye. M3 1 was once considered as a nebula, and the identity of its galaxy was not confirmed by Hubble until 1924. If we observe with simple binoculars, we can find that M3 1 is surrounded by two companion galaxies: M32 in the south and M 1 10 in the north. Among these interesting celestial bodies, it is certain that Andromeda γ is a binary star system, consisting of an orange giant star and a blue little star.