Some archaeoastronomers ,mainly continental e.g. Claus Clausen in Denmark and Marciona Da Silva in Spain ,have noted that the orientation of some passage grves and chambered cairns are aligned towards the east but are out by up to 15 degrees .They suggest that when good dates are available for the construction of the building the orientation is towards the rising full moon immediately before or after the equinox . If this full moon is also 180 degrees from a setting sun there is a 30% chance of a lunar eclipse .
Alasdair Whittle is very confident that recent R.C. dating combined with Bayseian statistics can provide dates that are accurate up to a decade . The resultant date for West Kennnet long barrow was dated 3460 cal BC The barrow is aligned is aligned 85 degrees +or - 1
Eleven days before the spring solstice in 3640 BC a full moon rose at 85 degrees and the sun set at 236 .This is an example of archaeoastronomy that is impossible to witness , like many lunar “alignments “ or eclipses , and all we have to go on is figures like the bearing of the monument . You could always argue that the orientation is actually towards the equinox and it's just out by a few days but there are others equally off ,the equinox but fitting into the "negalithic moon " interpretation . Of course like all that kind of stuff it could be bollocks . Any thoughts , particularly negative ones more than welcome .