We are used to years with two Easters, and two chances to guzzle chocolate eggs, but this year there are three!
In 2019, the vernal equinox is at 21:58 UCT on Wednesday, 20th March. The full moon is 01:42 UTC on Thursday 21st March. So Easter, the first Sunday after the first full moon after the equinox, is on 24th March 2019.
Catholic and Protestant Christian churches use a theoretical equinox and a theoretical moon, which don’t accurately keep track of the real world, and so their Easter is 21st April. Orthodox Christian churches use a different theoretical equinox and moon, which is even worse at tracking the real world, and so their Easter is 28th April.
Bede, in The Reckoning of Time, describes Ēostre, supposely a pagan English deity, who gave her name to the month Ēosturmōnaþ. The idea of the first Sunday after the full moon after the vernal equinox seems to me to be connected to spring, and to light. The equinox has equal light and dark, the full moon lights the night all night; and Sunday is named for the sun so I suppose is the “brightest” day of the week. Lining them all up in this way, and delaying each after the next, gives a kind of ultimate bright day and night. I wonder if we are meant to stay up all night, and then look in the morning to see both the just-past-full moon and the sun above the horizon opposite one another.
My header image shows a screenshot from https://stellarium-web.org/