Lunar Rhythms in Religious Calendars
Celebrations of Easter, Passover, and Ramadan are linked to the lunar cycle primarily because, historically, lunar or lunisolar calendars have been used for marking time and calculating the dates of these holidays. In other words, the basis is the change in the phases of the Moon, not the characteristics of the moonlight itself as reflected solar radiation.For example, for the Jews, a lunar calendar was initially established in which the year consisted of 12 months of 29 or 30 days – totaling about 354 days. This system determined the date for celebrating Passover. As explained in one source:"Originally, the Jews had a lunar calendar in which the year consisted of 12 months with 29 or 30 days each. The year comprised 354 days, i.e., it was shorter than the solar year by more than 11 days. Starting roughly from the 4th century BC, this system of reckoning was displaced by a more complex lunisolar calendar. Its refinement continued over several centuries, and the basic astronomical calculations used to construct the calendar were first published in AD 359 and have essentially remained unchanged to this day. Briefly summarizing its core idea: Since the lunar year lasts 354 days, to reconcile the solar year (364 days) with the lunar cycle, an additional 13th month is periodically introduced." (source: link txt)For Muslims, a lunar calendar is characteristic, constructed solely based on the changes in the lunar phases. In this calendar, the year always consists of 12 synodic months, and the duration of a synodic month is approximately 29.53 solar days. Such calculations allow religious dates, like Ramadan, to be tied to observable lunar phenomena:"Muslims use a lunar calendar in which the year always consists of 12 lunar months — synodic months. One synodic month is the period of time between two consecutive identical phases of the Moon. Today, the duration of a synodic month is approximately 29.53058 average solar days. The lunar calendar is built solely on the changing phases of the Moon. The lunar year equals 354 or 355 days. However, adding extra days or months is prohibited, except for one day inserted to keep the new moon near the first day of the month." (source: link txt)Thus, even though moonlight is in nature a reflection of sunlight, it is the cyclicity of the lunar phases that provides a practical and observable means of measuring time for calculating the dates of important religious celebrations. The long-established traditions and astronomical calculations were based on the lunar cycle, making it crucial in determining the timing of celebrations like Easter, Passover, and Ramadan.Supporting citation(s):"Originally, the Jews had a lunar calendar in which the year consisted of 12 months with 29 or 30 days each. The year comprised 354 days, i.e., it was shorter than the solar year by more than 11 days. Starting roughly from the 4th century BC, this system of reckoning was displaced by a more complex lunisolar calendar. Its refinement continued over several centuries, and the basic astronomical calculations used to construct the calendar were first published in AD 359 and have essentially remained unchanged to this day. Briefly summarizing its core idea: Since the lunar year lasts 354 days, to reconcile the solar year (364 days) with the lunar cycle, an additional 13th month is periodically introduced." (source: link txt)"Muslims use a lunar calendar in which the year always consists of 12 lunar months — synodic months. One synodic month is the period of time between two consecutive identical phases of the Moon. Today, the duration of a synodic month is approximately 29.53058 average solar days. The lunar calendar is built solely on the changing phases of the Moon. The lunar year equals 354 or 355 days. However, adding extra days or months is prohibited, except for one day inserted to keep the new moon near the first day of the month." (source: link txt)