Cassiopeia.
A conspicuous W-shaped constellation near the north celestial pole. It is represented by the seated figure of Queen Cassiopeia of classical mythology, and was among the constellations listed by Ptolemy (c. AD 140). It is the site of a supernova observed by Tycho Brahe in 1572 and of the strongest radio source in the sky, a supernova remnant known as Cassiopeia A.