The brightness of the planets and stars is something most of us forget due to the interference of street lights and such .... I know when I'm in Wales at me caravan or me mum's house the sky is positively littered with the little buggers !! Even where I am I can look out from the edge of the estate over ye Wicklow Mountains and see such a profusion of stars ... a view I'd forgotten about living back in Birmingham !!

There is a good (and maybe out of print) book called The Stars And The Stones (or vice-versa) which is a report on one mans studies of Irish sites. I can't say how good it is because I haven't got it, but what I do know is that many of the tombs at Loughcrew have Lunar alignments rather than solar, I believe there are some other planetary ones too. Another very famous one is Queen Maeve's grave in which the passage aligns to the furthest northern point of the moon's travels ... a place it reaches only once every 18.5 years!!

There is of course no reason why all these theories can not be true, either dating from different periods or being used by different cultures simultaneously.