I think that they're suggesting that this would be conventionally the case: "Okay, we're now deciding that Easter Sunday will be April 15, which is always a Sunday."
I think this is on the basis that it's important for Easter to be on a Sunday, and not nearly as important that it be the Sunday following the first full moon following the equinox, or whatever: just that once you say "it's got to be on a Sunday," you need some damn way to figure out which Sunday each year.
But Easter moves around quite a bit during the year, sometimes being on the 83rd day of the year (in 2008), sometimes on the 110th day of the year (2014), and various dates between. I don't see how changing to a 13 month calendar would affect the first full moon after the spring Equinox, since the lunar cycle doesn't mesh with the solar one.
> I don't see how changing to a 13 month calendar would affect the first full moon after the spring Equinox, since the lunar cycle doesn't mesh with the solar one.
Just checked... you seem to be correct. The lunar calendar isn't aligned with this well enough. While the equinox date is fixed, the first full moon after that should bounce around by several days at least. Even allowing that it's always the Sunday after that, it still seems as if it could fluctuate by a week in either direction.
See also the 'Synod of Whitby' (Whitby is also famous for Dracula - I'm not sure if that's related, but if you're a goth or easter-history fan it's a great place to visit! ;-) :
I think this is on the basis that it's important for Easter to be on a Sunday, and not nearly as important that it be the Sunday following the first full moon following the equinox, or whatever: just that once you say "it's got to be on a Sunday," you need some damn way to figure out which Sunday each year.