As Hallowe’en approaches, look for the star Algol, the “ghoul” that marks the head of the hideous monster Medusa, a great Hallowe’en costume! Look northeast at 7:30, where the brightest star in Perseus, Mirfak appears (not to be mistaken for the brighter Capella below). To the right of Mirfak, a little lower, shines the spooky Algol.
Hallowe’en’s connection to astronomy comes from its position on the calendar, halfway between the Autumnal Equinox and the Winter Solstice. This mid-point, known as a “cross-quarter day”, began the “dark” half of the year for Celtic people, ending on another season’s mid-point, May 1st, or May Day.
Vega, the brightest evening star, starts this night high in the west at 7 o’clock, and takes its time lowering through the northwest all evening, not setting until 2 o’clock tomorrow morning. Vega is bright, in part, because it is one of the closer stars to us, some 26 light years away, as well as cranking out 37 times as much light as our Sun.