# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Astro*Dictionary by Michael Erlewine





1 article for "Variation"

Variation [Astro*Index]

A periodic inequality in the Moon's orbit due to the gravitational attraction of the Earth and Sun. The effect is to accelerate the Moon's motion in its orbit at New Moon and Full Moon, and to retard its speed at First and Last Quarter. Its period is one-half the synodic month, or about 14.77 days, leading to a displacement in the Moon's Longitude of 39'29.9".

See also:
♦ Lunar Phases ♦ Evection ♦ Annual Equation ♦ Synodic Month


Astro*Index Copyright © 1997 Michael Erlewine