using Thom's analysis
Stonehenge is 84/100ths the size of Brodgar.
It is very easy to check, divide the diameter of SH Aubrey circle 285.60 feet by 0.84 to get 340 ( Also the Diameter of the Avebury inner rings )
Brodgar and Avebury are both linked to the eclipse line in my last book.
SH circumference 89760 can be translated by multiplying it by 56 x 52 to give an 8 year cycle represented by 261381120.
Divide this by 0.84 to get the Brodgar equivalent.
261381120 / 89760 is 2912 days or 8 solar years of 364 days.
311168000 / 89760 is 3466.6666r days or 10 lunar years of 346.666r days or 13 months of 26.666r days and this number links to the HSMF.
10 and 8 are represented and the reason why becomes very obvious using Thom's analysis.
As Barnatt explains in his book focussing on the rising and setting stars is a red herring and gives too many options (but still not to be discounted) but the main focus of the circles is the Sun and Moon.
130 or 260 or 520 is the denominator of Thom Pi.