And when you get in you can't get out . (For six months or so). I'll buy a protractor and get a better look at Thom's plan. There's a month or so before the shortest day. The principal alignment of the Avebury stones is +36 declination which A Thom guessed was the setting point of Deneb - one of the stars of Cygnus. The largest of the four stone rows in Bolton also inclines on this azimuth - maybe towards Deneb setting in those days, maybe not - but it shows that both sets of stones were put up about the same time, and in the same spirit.