Cassiopeia is named after the vain Greek mythological queen of Aethiopia, the wife of Cepheus and the daughter of Andromeda. This constellation was one of the 48 constellations cataloged by the 2nd century astronomer Ptolemy that remain among the 88 modern constellations. This 25th-largest constellation appears as either a distinct “M” (fall and winter) or “W” (spring and summer) shaped asterism of bright stars that often catches the eye of novice observers who happen to gaze in the right direction. Although it is a northern circumpolar constellation that can be seen year round, it is found high above Polaris in December, which is when it is most easily viewed. This constellation is located opposite of the Big Dipper from Polaris, so try finding it by starting at the Big Dipper, and tracing a line northward (upward) through Polaris until reaching the first grouping of bright stars.
The Milky Way flows through Cassiopeia, and it contains two Messier objects, M52 and M103, both of which are open star clusters. It also contains numerous other NGC objects and two supernova remnants, including Tycho’s Star, a supernova recorded in 1572 by Tycho Brahe, and another remnant of a supernova that was seen 300 years ago. Interestingly, if our sun were observed from Alpha Centuari, our nearest solar neighbor 4 light-years away, it would appear to be located in Cassiopeia.
© James R. Johnson, 2014