Tag Archives: Double Cluster

Perseus (A Greek mythological hero)

PerseusCCThe constellation Perseus is located near several other constellations to which Perseus is related in Greek mythology: Cepheus, Andromeda, Pegasus, Cassiopeia, and Cetus. This constellation was one of the 48 constellations cataloged by 2nd century astronomer Ptolemy that remain among the 88 modern constellations. This easily spotted constellation is well placed high in the northern sky and best seen in January. It is found between Cassiopeia and the Pleiades, and Mirfak (Alpha Persei) is its brightest star Its most interesting star Algol (Beta Persei) is an eclipsing binary star. Its variable brightness, which is noticeable to the naked eye, decreases by over one degree of magnitude for about ten hours on a cycle time of just under three days. This star is also known as the Demon Star, because the ancients perceived its variability as an ominous sign. Also notable in this constellation is theNGC869NGC884 Double Cluster (NGC 869 and NGC 884), which are naked eye objects under very dark skies. Perseus is home to two Messier objects, M34 and M76, and to the Perseids meteor shower. This meteor shower, one of the most consistently prominent meteor showers each year, lasts from mid-July to late August, peaking between the 9th and 10th of August.

IAU Perseus chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 5, 2011.

© James R. Johnson, 2014.