ECLIPTIC

ECLIPTIC, the name given to the circular path in the heavens round which the sun appears to move in the course of the year, an illusion caused by the earth's annual circuit round the sun, with its axis inclined at an angle to the equator of 23½ degrees; is the central line of the ZODIAC, so called because it was observed that eclipses occurred only when the earth was on or close upon this path.