The calculator calendar is the most common in the Islamic world the secular (civil) calendar, the beginning of the month, is determined astronomically. The Julian calendar (the Gregorian did not yet exist) was July 16, 622 A.D. The days of the Muslim calendar are counted from the sunset, so the sunset of the previous day started 1 day 1 month 1 year of exile (Anno Hegiræ, A.H.) The beginning of chronology or the era(see Old Russian (Byzantine) system of chronology) in the Muslim calendar is the date of the expulsion of Mohammed from Mecca to Medina, or Hidzhry ( Hegiræ). Therefore, for example, the month of Ramadan, whose name in Arabic means "to burn", may happen in the winter. However, in 631 AD, the Prophet Muhammad has forbidden to add these days and the Muslim year became strictly lunar. Generally speaking, earlier, in pre-Islamic times, the Arabs used a solar-lunar calendar, and there was a 13 month, who introduced an amendment to the solar year so that the month remained tied to the seasons. Since the calendar is based on the moon and the lunar year is shorter than the solar year, the month is not tied to the seasons, and each year they are shifting for about 11 days relative to the solar calendar. Thus, the average length of the year will be approximately equal to 354.366(6) days, and the month will be equal to 29.5305(5) days, which is much closer to the length of the synodic month. Thus, every 30 years contains 19 normal years of 354 days and 11 leap years of 355 days. Leap years follow a 30-year cycle and fall on the 2, 5, 7, 10, 13, 16, 18, 21, 24, 26, and 29 years of the cycle. Without the introduction of leap years, the average duration of the year's months would be strictly 29.5 days, which would give us a big error. The last month consists of 29 days, and during a leap year is extended to 30 days. The well-known Gregorian calendar is solar, but the Muslim calendar is lunar.Ī year in the Muslim calendar consists of 12 months, which alternate between 30 and 29 days. Synodic month - the period of the Moon revolution around the Earth between the two new moons.ĭuration of the synodical month - 29.53059 daysĭuring the synodical month, there is a complete change of phases of the moon. Lunar calendar - calendar, which is based on the synodic month. Tropical year - the time interval between two successive passages of the Sun through the vernal equinox.ĭuration of the tropical year - 365,242196 daysĭuring the tropical year, there is a complete change of seasons. Solar calendar - calendar, which is based on the tropical year.
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