Measurement of Time, Seq’es, and Associated Rites

Astronomers define several different periods of revolution of the Moon. These include the sidereal period, which corresponds to two passages of the Moon at the same position in the sky in relation to the stars, the synodic period or lunation, which corresponds to the return of the Moon to the same position in relation to the Sun, and the tropical period, which corresponds to two successive passages of the Earth’s natural satellite at the same position in relation to the vernal point.