Metonic cycle
Noun
Meaning
Metonic cycle (plural Metonic cycles)
(astronomy, calendar studies) A particular approximate common multiple of the tropical year and the synodic month; in other words, the 19-year period over which the lunar phases occur on the same dates.
According to the Metonic cycle, a lunar calendar begins on the same solar date every 19 years.
Synonyms
Related terms
Examples
A Metonic cycle equates to 235 lunar months in each 19-year cycle.
Given the Tishrei molad of a certain year, the length of the year is determined as follows: First, one must determine whether each year is an ordinary or leap year by its position in the 19-year Metonic cycle.
Leap years The Jewish calendar is based on the Metonic cycle of 19 years, of which 12 are common (non-leap) years of 12 months and 7 are leap years of 13 months.
Meton 's cycle had an integer number of days, although Metonic cycle often means its use without an integer number of days.
The concert between the solar terms and the months, comply with the Metonic cycle in general.
The next approximation (arising from continued fractions) after the Metonic cycle (such as a 334-year cycle) is very sensitive to the values one adopts for the lunation (synodic month) and the year, especially the year.