Didn't someone (possibly Martin Brennan) say that the alignment from the entrance of cairn L at Loughcrew to the interior free-standing stone was aligned with an eclipse around the time of its erection? It may have been solar, though.
It's an interesting theory, but would a lunar eclipse be as big a deal as a solar eclipse? It would assume a lunar rather than solar cult. The moon's a cool thing, I admit, but was it bigger than the sun?