Search the Dictionary

, or, taking the sidereal day as the unit, the time elapsed since a transit of the vernal equinox, reckoned in parts of a sidereal day. This is, strictly, apparent sidereal time, mean sidereal time being reckoned from the transit, not of the true, but of the mean, equinoctial point.

ic year, the solar year; the period occupied by the sun in passing from one tropic or one equinox to the same again, having a mean length of 365 days, 5 hours, 48 minutes, 46.0 seconds, which is 20 minutes, 23.3 seconds shorter than the sidereal year, on account of the precession of the equinoxes.

nsion or declination of a star, produced by the combined effects of the precession of the equinoxes and the proper motion of the star. -- Calculus of variations. See under Calculus. -- Variation compass. See under Compass. -- Variation of the moon (Astron.), an inequality of the moon's motion, depending on the angul…

calendar. In this calendar, the year, which began at midnight of the day of the autumnal equinox, was divided into twelve months of thirty days, with five additional days for festivals, and every fourth year six. Each month was divided into three decades of ten days each, the week being abolished. The names of the mon…

The point in the heavens where the sun is seen to set at the equinox; or, the corresponding point on the earth; that one of the four cardinal points of the compass which is in a direction at right angles to that of north and south, and on the left hand of a person facing north; the point directly opposite to east. And…