It's self adjusting to #ClimateChange.
#MetonicCycle is not very accurate for #SiderealYears, the #SouthEastAsianCalendar is slowly drifting out-of-sync with the #sidereal, approximately one day every 100 years. Yet no coordinated structural reforms of the #LunarsolarCalendar have been undertaken.
The #MetonicCycle or enneadecaeteris (from #AncientGreek: ἐννεακαιδεκαετηρίς, from ἐννεακαίδεκα, "nineteen") is a period of almost exactly 19 years after which the #lunarPhases recur at the same time of the year. The recurrence is not perfect.
Depiction of the 19 years of the Metonic cycle as a wheel, with the Julian date of the Easter New Moon, from a 9th-century MS.
(link in comments)
#astrosphere #MetonicCycle
