UncleRob wrote:
The more one thinks about this question the worse it gets! I never got on with trigonometry, very confusing. I reckon there must be a site out there that does more flexible calculations of sun position. Given the Ordnance Survey Eastings and Northings (and elevation) of the passage tomb and the hill, you could work out the azimuth and elevation of the hill top from the tomb. Then you want to know when the sun passes through that point. Hmmm, I bet there are a few astronomy chatrooms out there where they would know how to get the answer straight away. (But, as AuntCaroline would say, Nerd Alert!)
Working from OS maps is not too accurate , although Thom was not averse . What is imporatnt is the declination which includes all the info , heights , distance ,latitude , and azimuth . That info is the minimum then there is the much smaller problems of refraction and parallax .The formula as given by Ruggles etc is sin latitude sin height+cos latitude cos height cos azimuth =sin declination
it is sunday so sorry about that .
