I can't say I'm actually surprised by this - I'd found exactly the same when celebrating Full Moons (i.e., a Full Moon Esbat ritual) over the last few decades: the energy is so close to the same for about a three or four day period, that I have no hesitation in shifting the time I have a full moon by a day or two from the official, "exact" time of the 100.00000% full moon.
I do, however, have some restrictions on shifting the timing of a New Moon Esbat ritual. To some extent, this is possibly because the rituals I have been doing are looking at celebrating/facilitating/working with new beginnings, or things I wish to have grow. That means I actually want to celebrate in the period when the Moon is New, not dark, and growing - which means I do the ritual within a day or so AFTER the New Moon becomes visible.
Thinking back, I have not actually performed any Dark Moon Esbats that I can recall ... hmmm. I'll have to tune into the energies at that time, and see what I can work out/learn ...
When I first started doing Full Moon rituals, I was fumbling in the dark, and didn't know that Wicca also could observe Dark/New Moons (as a Cancerian I tend to naturally gravitate towards a Full Moon, and just feel lousy when She isn't shining in her full glory :) - by the way, I'm sorry about the puns ... I think :D ). After I started my formal study and found out that such things were possible, i was probably too much of a fluffy white-light bunny to consider doing anything that had the word "Dark" in it. Now ... I just can't actually think of anything I would. Hmm. That's scary - I sound FAR too innocent and fluffy white-light bunny :)
Love, light, hugs and blessings
Gnwmythr

This post's photo is yet to be posted.
Tags: rituals, timing, Litha, midsummer, Sabbats limitations, Esbats, full moon, dark moon, new moon,
First published: Wodansdagr 22nd December, 2010
Last edited: Wednesday 22nd December, 2010