Lunar month with the Sun one or two days before that evening ("e.g.", in the Islamic calendar). In ancient Egypt the lunar month began on the day when the waning moon could no longer be seen just before sunrise. Others use calculation, of varying degrees of sophistication, "e.g.", the Hebrew calendar or the ecclesiastical lunar calendar. Yet others run from full moon to full moon. Calendars count integer days, so months may be 29 or 30 days in length, in some regular or irregular sequence. In India the month from conjunction to conjunction is divided into thirty parts known as "tithis". The
Lunar month has been observed among cultures in the Middle East, India, and China in the following way: they divided the sky into 27 or 28 lunar mansions, one for each day of the month, identified by the prominent star(s) in them. The synodic month (, "synodikós", meaning "pertaining to a synod, i.e., a meeting"; in this case, of the Sun and the Moon) is the average period of the Moon's orbit with respect to the line joining the Sun and Earth. This is the period of the lunar phases, because the Moon's appearance depends on the position of the Moon with