It’s become a kind of tradition to talk about various holidays every year, but the problem is that it’s hard to say something different every year — there’s only so much to be said for most holidays. Easter is no exception…. after a few years the discussion about the real meaning and importance of Easter and the Easter Bunny, chocolate eggs, egg hunts, etc. begin to sound like a broken record.
Anyhow, I thought this year I’d focus on Easter being a “movable feast.” Easter occurs on the first Sunday after the “Paschal Full Moon” — that means the first full Moon immediately following the vernal (spring) equinox. Of course, like most things, it’s more complicated than that — because Easter isn’t based on the actual Moon or equinox date…. here’s the connection between the Moon and Easter.
I mentioned that Easter is what’s known as a movable feast — that means that Easter jumps around the calendar and is a religious holiday that falls on a different calendar date from year to year.
The date of Easter is tied to the relationship between the Paschal Full Moon — whose dates are based on calculations made long ago, and the Church’s fixed date of the March equinox (the spring or vernal equinox in the Northern Hemisphere) which is March 21. This makes determining when Easter will be more confusing because of the (occasional) differences between the “Church dates” and the astronomical dates.
Here’s the “rule-of-thumb” I found for determining the date:
“Easter is observed on the Sunday following the first full Moon that occurs on or after the March equinox.” But occasionally, as I said, the Church’s dates don’t coincide with the astronomical dates, in which case the “rule-of-thumb” won’t apply.
First, let’s define the terms:
The astronomical dates of the full Moon and the March equinox are the actual, scientifically determined dates of those events.
The Church’s dates of the full Moon and the March equinox are those used by the Christian Church. They were defined long ago in order to aid in the calculation of Easter’s date. That means that they may differ from the astronomical dates of those events.
In A.D. 325, a full Moon calendar was created that did not take into account all the factors of lunar motion that we know about today. The Christian Church still follows this calendar, which means that the date of the ecclesiastical full Moon may be one or two days off from the date of the astronomical full Moon. And — the astronomical date of the equinox changes over time, but the Church has fixed the event in their calendar to March 21. This means that the Church date of the equinox will always be March 21, even if the astronomical date is March 19 or 20,
Using the astronomical dates for 2023, the vernal equinox in the Northern Hemisphere occurred on Monday, March 20. The first full Moon to occur after that equinox date is April’s full Pink Moon, that reached peak illumination on Thursday, April 6 at 12:37 a.m. Eastern Time. According to the rule-of-thumb, that makes April’s full Moon the Paschal Full Moon [“Paschal” comes from Pascha, the Greek and Latin word for Passover] so Easter is observed on the first Sunday after April 6 — that’s today, April 9.
Happy Easter!
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