1st Sunday on or after the first full moon after the equinox.
I think?
But I'm grateful someone else does all the calculations for me!
It is, but it's the Pascal Full Moon, which is a mathematical construct that closely approximates the full moon.
It's not hard. I used the method found here in this PDF of the Doomsday Rule:
http://people.se.cmich.edu/graha1sw/pub/doomsday/doomsday.pdf . The Doomsday Rule is a way of calculating the day of the week for any date. Just knowing what days of the month of a year fall on the same day of the week as the last day of February makes a handy mental calendar. Anyway, in this PDF is a way of calculating Easter.
The Golden Number, the number used in Easter Charts, is easy, since it's a cycle of 19: Golden Number = the remainder of the year divided by 19, plus 1. There is another variable, C, which changes under the Gregorian Calendar, but is a constant for the Julian Calendar. For the Julian Calendar, C = 3. For the Gregorian Calendar there's a formula based on the Century Year (for 2022, the Century Year is 20). It's C = -Century Year + integer portion of (Century Year / 4) + integer portion of (8 x (Century Year + 11) / 25). Fortunately, we don't have to calculate C every time. C = -5 for centuries 1700 and 1800, and C = -6 for centuries 1900 and 2000
The Golden Number and C are put together to calculate the Pascal Full Moon: Pascal Full Moon = April 19 - remainder of (Golden Number x 11 + C)/30 = March 50 - remainder of (G x 11 + C)/30. So, for 2023, G = 10 and C = -3, so March 50 - remainder of (11 x 10 - 6)/30 = March 50 - remainder of 104/30 = March 50 - 14 = March 36. But there's no such thing as March 36, so March 36 - 31 = April 5. So the Pascal Full Moon for 2023 is on April 5, 2023. If it has fallen on April 19, we would have used April 18, and if it was April 18 and the Golden Number was greater than or equal to 12, we would have used April 17.
Based on the Doomsday Rule, April 4, 2023 falls on Tuesday, so April 5, 2023 falls on Wednesday. That means Palm Sunday falls on April 2, 2023, Good Friday on April 7, 2023, and Easter April 9, 2023.
It really takes more to explain it can to calculate it. It can look daunting, but it's not that difficult The hard part for me is dividing by 19 in my head.
The PDF in the link above also tells how to calculate Rosh Hashana, but I haven't memorized that.
If you do this for Julian years and check the results online, beware that some online results give the value in the Gregorian Calendar only.