Easter and the Moon
Here's a photo of the nearly full moon, the night before Good Friday, complete with church dome in the background, taken from Dodecahedron Books corporate headquarters :).
Besides being a pretty scene, the picture ties together the moon and the church, just as Easter does. Easter is defined to fall on the first Sunday after the first full moon after the vernal equinox (roughly speaking, the point in spring where the day and night are the same length). That means that Easter can fall anywhere between March 22nd and April 25th. Historically, determining the date for Easter was the most important task that was given to the Vatican Astronomer. Note that there are complications arising from the fact that the astronomical and ecclesiastic calendars differ somewhat. There are a surprising number of books that have been printed on this subject, over the centuries.
This raises the question of why Easter is defined in relation to the moon. One factor is that the Jewish calendar is partly lunar and since Passover is defined relative to lunar cycles, Easter is too, as the Resurrection was supposed to be the first Sunday after Passover. So, the linkage to the moon is really just a consequence of the linkage of Easter to Passover.
Another theory that I have read is that making Easter dependent on the full moon ensured that pilgrims to the holy land had long moonlit nights before Easter, allowing them to travel through the night. That seems fanciful to me, as it seems to presuppose that pilgrimages occurred at a set speed, and started from a particular point.
Of course there is also the notion that the Christian Church co-opted Pagan rituals of spring when it came up with its Easter celebration – if you can't beat them, join them, then take them over from within. The word Easter, for example is thought to come from the Saxon word Eostre, goddess of the moon. This deity was thought to measure time, a natural enough response of early people to the apparently unvarying cycles of the moon. Perhaps, then, it is no surprise that the new religion would want to show potential converts that it, too, had an important symbolic links to this mysterious heavenly body, in its most sacred of holy days.
So, perhaps the connection of Easter with the first full moon after the spring equinox might be seen as a sort of mash-up of Pagan rites of spring with lunar aspects of the Jewish lunar.
By the way, this Saturday night (the night before Easter) will feature a lunar eclipse. Totality will be very short, though, owing to the specifics of the moon's orbit at this time, relative to the plane of the ecliptic.
And don't forget that Helena Puumala's Easter short story is now free on Amazon up to and including Easter Monday :).