Turning point at the solstice stones

The north east of Scotland is rich in neolithic monuments, and in particular there are many hundreds of stone circles and standing stones.  One particular type of circle, the recumbent circle is found only here in Aberdeenshire (nearly 100 examples) and some in the south west of Ireland. 

One of the nearest circles to home is also one of the more complete examples, at Cothiemuir Hill.  I've written about this circle previously here and here, and I continue to find the place absolutely compelling.  Now within a wood, the circle is on a low hill and would have had good open views during its period of use around 2700-2500 BC.

The 2.9 metre tall west flanker is aligned precisely to the midwinter moon when viewed from the centre of the circle.  This is the orientation of almost all the recumbent circles, so it's no coincidence. Even more remarkably, the alignment is designed to frame the standstill moon which occurs every 18.6 years....how did the neolithic people calculate this?!  The movement of the setting sun seems also to have played a part in the alignment, and I've tried to recreate this by taking an image offset from the centre of the circle a few days before the winter solstice.

It really isn't difficult to imagine the people who built this sophisticated and massive undertaking marking out the days shortening, recording the apparent two day standstill at the solstice, and then the slow lengthening of the days as the year is reborn.  Nor is it hard to empathise with why this mattered to them so much.

We try to visit as close to the winter solstice as we can, not from any new-age belief, just from a simple, instinctive feeling that this is their time in the year.