1911 Encyclopædia Britannica/Perseus (astronomy)

PERSEUS, in astronomy, a constellation of the northern hemisphere, called after the Greek legendary hero. it is mentioned by Eudoxus (4th century B.C.) and Aratus (3rd century B.C.); Ptolemy and Tycho Brahe catalogued 29 stars, Hevelius 46. The most important member of this constellation is β Persei or Algol (q.v.), a famous variable star. θ Persei is a triple star, composed of one 4th magnitude star and two of the 10th magnitude; ρ Persei is an irregular variable, with a range in magnitude of 3.4 to 4.1. Nova Persei is a “new” star discovered in 1887 and subsequently recognized on Harvard plates by Mrs Fleming in 1895; another new star was discovered by Anderson on the 21st of February 1901, which, after increasing in magnitude, gradually became fainter and ultimately disappeared. There is a nebula surrounding Nova Persei (1901) which was photographed at Yerkes observatory in September 1901; a pair of star clusters, appearing as a bright patch in the Milky Way; and the meteoric swarm named the Perseids, which appear in August and have their radiant in Perseus. (See Meteor.)