Andromeda (constellation)

Andromeda is a constellation representing the princess Andromeda, in the northern sky near Pegasus. The constellation takes the general shape of a long, dim, straggly letter "A". It is most notable for containing the Andromeda Galaxy.

Notable features

The brightest star in Andromeda, α Andromedae, called Alpheratz or Sirrah, makes up with α, β, and λ Pegasi an asterism called the Great Square of Pegasus. This star was once considered part of Pegasus, as confirmed by its name, "shoulder of the horse."

β Andromedae is called Mirach, the girdle. It is 88 light years distant and of magnitude 2,1.

γ Andromedae, or Almach, is found at the tip of the southern leg of the big "A". It is a beautiful multiple star with contrasting colours.

υ Andromedae has a planetary system with three confirmed planets, 0.71 times, 2.11 times, and 4.61 times the mass of Jupiter.

Notable deep sky objects

The most famous deep sky object in Andromeda is M31, the Andromeda Galaxy, the most distant object visible to the naked eye. It is an enormous spiral galaxy much like ours. To find the galaxy, draw a line between β and μ Andromedae, and extend the line approximately the same distance again from μ.

Mythology

Andromeda was a princess condemned to be sacrificed to a sea monster; she was rescued by the hero Perseus. See Andromeda for the full account of the myth. Such figures from the myth as her mother and father, Cassiopeia and Cepheus[?], Perseus and his winged horse Pegasus, and the sea monster Cetus are all commemorated by nearby constellations.