Lunar month circular, the speed of Earth's progression around the Sun varies during the year. Thus, the angular rate is faster nearer periapsis and slower near apoapsis. The same is so for the Moon's orbit around the Earth. Because of these variations in angular rate, the actual time between lunations may vary from about 29.18 to about 29.93 days. The long-term average duration is days (29 d 12 h 44 min 2.8016 s). The synodic month is used to calculate eclipse cycles. It is customary to specify positions of celestial bodies with respect to the vernal equinox. Because of Earth's precession of
Month calendar consists of both a lunar calendar and a solar calendar. The Khmer solar calendar is used more commonly than the lunar calendar. There are 12 months and the numbers of days follow the Julian and Gregorian calendar. The Khmer lunar calendar contains 12 months; however, the eighth month is repeated (as a "leap-month") every two or three years, making 13 months instead of 12. The Tongan calendar is based on the cycles of the moon around the earth in one year. The months are: The Sinhala calendar is the Buddhist calendar in Sri Lanka with Sinhala names. Each full