LIBRA (" THE

See also:

• BALANCE (derived through the Fr. from the Late Lat. bilantia, an apparatus for weighing, from bi, two, and lanx, a dish or scale)

BALANCE ")  , in astronomy, the 7th sign of the zodiac (q.v.), denoted by the symbol =, resembling a pair of scales, probably in allusion to the fact that when the sun enters this part of the ecliptic, at the autumnal equinox, the days and nights are equal . It is also a constellation, not mentioned by Eudoxus or Aratus, but by Manetho (3rd century B.C.) and Geminus (1st century B.C.), and included by Ptolemy in his 48 asterisms; Ptolemy catalogued 17 stars, Tycho Brahe 1o, and Hevelius 20 . S Librae is an Algol (q.v.) variable, the range of magnitude being 5•o to 6.2, and the period 2 days 7 hrs . 51 min.; and the cluster M . 5 Librae is a faint globular cluster of which only about one star in eleven is variable .