Ecliptic, the great circle of the heavens along which the sun appears to travel in the course of a year. It is inclined at an angle of about 23° 28' to the celestial equator. The name is derived from the fact that the light of the sun or moon can only "pass away" when the moon is on or near the ecliptic. The ecliptic is divided by astronomers into 12 equal portions, each of 30°. These are called signs, and supply the means of indicating the annual progression of the sun. They commence with the point where the ecliptic crosses the equator passing from south to north. This point is called the first point of Aries, and is indicated by the sign ; and Aries extends 30° along the ecliptic eastwardly, that is, in the direction of the sun's motion, from this point. Then follow successively the signs Taurus Gemini Cancer Leo Virgo Libra Scorpio Sagittarius Capricornus
Aquarius and Pisces These signs, whether regarded as ecliptical or zodiacal, are not identical with the corresponding zodiacal constellations, each of which, owing to precession, has been carried so far forward as to agree very nearly with the next sign. Thus the constellation Pisces corresponds very nearly with the sign Aries, the constellation Aries with the sign Taurus, and so on. The sun enters Aries at the vernal equinox, on or about March 21, Taurus on or about April 20, Gemini on or about May 21, Cancer on or about June 21 (the summer solstice), Leo on or about July 22, Virgo on or about Aug. 23, Libra on or about Sept. 23 (the autumnal equinox), Scorpio on or about Oct. 23, Sagittarius on or about Nov. 22, Capricornus on or about Dec. 21 (the winter solstice), Aquarius on or about Jan. 20, and Pisces on or about Feb. 19.