On what does the date of Easter depend each year?
-The date on which Fat Tuesday falls
-The date on which Groundhog’s Day is celebrated
-The number of weeks between Ash Wednesday and St. Patrick’s Day
-The date on which the paschal full moon appears
The date for the celebration of Easter each year is determined by the appearance of the full moon. Easter is traditionally celebrated on the first Sunday following the first full moon that occurs on or immediately after the vernal equinox. This full moon is known as the “paschal full moon.”
To keep things simple, the Catholic Church set a fixed date for the vernal equinox as March 21. Astronomically, however, the vernal equinox may actually occur on the 19th or 20th. The paschal full Moon arrives on the 14th day in the lunar month. Source: Almanac.com
The date on which the paschal full moon appears
The date of Easter is determined as the first Sunday after the “paschal full moon” falling on or after the Spring Equinox (March 21). This “full moon” does not currently correspond directly to any astronomical event, but is instead the 14th day of a lunar month, determined from tables.