The scientific method of isolating one factor and to assume that this process will tell you the truth is a very modern habit. The hills and valleys and presence of older monuments were undoubtedly a part of the whole story because there is no reason why they should not be.
My problem is: petrol, time, choice...family...money, where do I begin to start making observations and what exactly am I trying to find out anyway!?
I wish I knew the answer to that!
As far as I know we don't have any continuity of country folk and their folk tales; do we have any indigenous folk tales and myths recording where the sun and moon rise, or stories linked to structures said to have been used for this purpose?
The most famous folk tale about the moon tells of how she was lost in the bog lands; the full moon being a power to keep the evil things at bay.
Which evokes gruesome images of bog bodies and human sacrifice taking place on the darkest nights...
Real interest in the sun and moon, in Britain at least- comes to the fore in the fifteenth century when Charles II appointed John Flamsteed as his first Astronomer Royal in March 1675.
Navigation was the problem, time had to be fixed.
Before then, it is hard to find any real focus on alignments. It is true that Christian churches were built incidentally at first, with solar alignments- facing East towards the center of the world, Jerusalem.
Latter the orientation became more specific, sun-rise on the saints day or so I have been told.
But is that only true of churches dedicated to Saint John the Baptist?
It is also true that churches were often built on prehistoric sites, and so any odd celestial event that had causes the site to be marked with a stone circle or barrow of some kind, would not be linked to Christianity as such, but would become a part of the church.
Such as the Leek double midsummer sunset
Generally speaking it is possible to tell roughly where we are in the year by recording the position of a full moon as it rises and sinks below the horizon. So for calender purposes, sun and moon rise could be done anywhere more or less within the same latitude except the horizon it wobbly- with hills and trees and rocks making one's life difficult!
I don't know if anyone ever recorded if this was done or how, and anyway why bother when it is so much easier to use the sun?
But people do use the moon...
'We' still use it to determine the date of Easter.
Dee's Sigillum Dei Aemeth [late sixteenth century]- possibly a thirteenth century amulet -embodies 'Babylonian' concepts of angelic forces and planets; a complex weaving of names and numbers...but there is nothing like that in British prehistory is there?
The Babylonian's tried to control the damage done by bad stars and ill omens; they needed to predict the positions of the sun and moon and planets.
Did the people who made Woodhenge need to do this too?
It is very easy to come up with bizarre and complex interpretations. Eighteenth century William Stukeley  noted the summer solstice alignment at Stonehenge, and began his Druid revival. For Stukeley Stonehenge and similar stone circles had been serpent temples, the serpent being Christ and the original Druids lost Phoenicians or Hebrews who had brought 'the true religion' to Britain.
Excuse me if I fail at this moment to take it too seriously!
Ultimately Woodhenge and The Sanctuary are mysterious places, because I cannot find any continuity in basic beliefs between then and now, the only similar round structures we still build today are roundabouts!
I do mean traffic roundabouts....and this proves to me at least that continuity [of form] isn't always as meaningful as I'd like it to be.
If I stretch the facts a lot to make a continuity between modern traffic roundabouts and prehistoric circles, I could say that places as Woodhenge were probably meeting places and that tracks would have existed leading from one destination to another, many paths meeting at Woodhenge or Durrington.
But this line of thought doesn't really get us any closer to sun and moon observations does it!
The image to the left is one of the beautiful structures of Jantar Mantar observatory, built in India in 1772- The Ram Yantra.
Both the interior walls and the floor of the structure are engraved with scales measuring the angles of azimuth and altitude. For measuring the azimuth, circular scales with their centers at the axis of the cylinder are drawn on the floor of the structure and on the inner surface of the cylindrical walls. The scales are divided into degrees and minutes.
For measuring the altitude, a set of equally spaced radial lines is drawn on the floor. These lines emanate from the central pillar and terminate at the base of the inner walls. [download a pdf that explains it]
If I was going to make it anywhere it would be on high, flat land, preferably with surrounding hills far enough away on the horizon as to just give me a reference point and not get in the way of the horizon.
I would want lots of posts.
But why would I need to do this?
Usually the answer here is to predict solar and lunar eclipses...which can be 400-800 years apart. Why would anyone bother with that!
I'm grateful to William H. Calvin for helping me to think about this.
10 miles east of the northern end of Sea of Galilee Rujm el Hiri.
Richard Benishai has photographs and an account of his visit.
This is a massively enhanced picture...
Rujm el Hiri. is a megalithic complex consisting of a large central tumulus surrounded by a series of low concentric stone walls, the largest measuring nearly 500 feet in diameter.
And then in Russia there is Arkaim.