nigelswift wrote:
Oh blimey you had me going there!
The maximum difference of rise and set angles in the UK is between 20-40 .Near the solstices it changes quicker than at the equinoxes . Actually, I bet it DOES get adopted as a.... well, you know the rest.
I suppose the sun adopts a different roll angle every day so it was bound to happen one day in the year. Ditto all of Tesco's roofs.
It needs the sun to set or rise at the same angle as the slope but also be in the right place to allow it to be seen , so no guarantees even with hills /man made mounds with the right angle . The horizon is very imporatnt too .If the horizon from the palidaded enclosure was higher it wouldn't work , i.e. if Waden Hill wasn't in the way you might have seen a "roll up " .They are quite common but go unnoticed because people don't stand about or don't happen to be in the right spot at the right time .