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Ursa Major

URSA MAJOR (" THE GREAT BEAR "), in astronomy, a constellation of the northern hemisphere, supposed to be referred to in the Old Testament (Job ix. 9, xxxviii. 22), mentioned by Homer, "ApKToj 6', fy /cat a/j.a^av iiriK\rjai.v xaXeoyrat (//. 18. 487), Eudoxus (4th century B.C.) and Aratus (3rd century B.C.). The Greeks identified this constellation with the nymph Callisto (q.v.), placed in the heavens by Zeus in the form of a bear together with her son Areas as " bear- warder," or Arcturus (q.v.); they named it Arctos, the she-bear, Helice, from its turning round the pole-star. The Romans knew the constellation as Arctos or Ursa; the Arabians termed the quadrilateral, formed by the four stars a, ft, y, 5, Na'sh, a bier, whence it is sometimes known as Ferelrum majus. The Arabic name should probably be identified with the Hebrew name 'Ash and ' Ayish in the book of Job (see G. Schiaparelli, Astronomy in the Old Testament, 1905). Ptolemy catalogued 8 stars, Tycho 7 and Hevelius 12. Of these, the seven brightest (a of the 1st magnitude, /3, y, e, f , if of the 2nd magnitude, and 5 of the 3rd magnitude) constitute one of the most characteristic figures in the northern sky; they have received various names Septentriones, the wagon, plough, dipper and Charles's wain (a corruption of " churl's wain," or peasant's cart). With the Hindus these seven stars represented the seven Rishis. a and /3 are called the "pointers," since they are collinear with, or point to, the pole-star. Ursae majoris is a beautiful binary star, its components having magnitudes 4 and 5; this star was one of the first to be recognized as a binary i.e. having two components revolving about their common centre of gravity and the first to have its orbit calculated, f Ursae majoris is perhaps the best known double star in the northern hemisphere, the larger component is itself a spectroscopic double. The nebula M. 97 Ursae majoris is of the planetary type; the earl of Rosse observed two spiral condensations turning in opposite directions, hence its name, the " Owl nebula."

Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)

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