Andromeda is a northern
constellation representing the mythological Andromeda, daughter of
Cepheus and
Cassiopeia and later wife of
Perseus, whom
Poseidon chained to a rock to be sacrificed to a sea monster. Andromeda is one of the 88 modern constellations, and was also one of the 48 listed by
Ptolemy. It is mainly notable as the location of the [Andromeda Galaxy]
?, M31.