Vernal Equinox is March 20 or 21, the ecclesiastical full moon is the 14th day of a tabular lunation (new moon), and Easter falls on the first Sunday following the first ecclesiastical full moon that occurs on or after the day of the vernal equinox.
春分是3月20日或21日，教會滿月是平月（新月）的第14天，復活節是春分當天或之後出現的第一個教會滿月之後的第一個星期日。
The first day of each of these lunar months is the ecclesiastical new moon. Exactly one ecclesiastical new moon in each year falls on a date between March 8 and April 5, both inclusive.
This begins the paschal lunar month （逾越節農曆月）
for that year, and thirteen days later (that is, between March 21 and April 18, both inclusive) is the paschal full moon.
Easter is the Sunday following the paschal full moon.
In other words, Easter falls from one to seven days after the paschal full moon, so that if the paschal full moon is on Sunday, Easter is the following Sunday. Thus the earliest possible date of Easter is March 22, while the latest possible date is April 25.
EG, in 2024 vernal equinox is on 20 Mar.
First full moon after vernal equinox is 24 Mar.
The following Sunday is 31 Mar, which is Easter Sunday.
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From Jan Meeus:
Spencer Jones - General Astronomy archive 1922
SH Butcher ecclesiastical calendar archive 1876. Very detailed explanation of different methods, but somehow difficult to read
Golden number:
A number in the 19-year cycle of the Moon, used for determining the date of Easter. (The Moon repeats its phases approximately every 19 years.) ie Metonic cycle. After a lapse of 19 years, the moon phases recurr on the same day and same month
Add 1 to any given year and divide the result by 19; the remainder is the Golden Number. If there is no remainder, the Golden Number is 19.
Starting 2000, Golden Number is (year -2000) mod 19
From ChurchOfEngland:
Reference:
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