What is the asterism of Cassiopeia?
The Queen’s second asterism is the Three Guides, but only one of the three stars — Beta Cassiopeiae — lies in the constellation. The other two stars are Alpha Andromedae and Gamma Pegasi. Now, here’s some trivia for you celestial navigators: Together, these three stars mark the equinoctial colure, the great circle that intersects both poles and both equinoxes.
