gjrk wrote:
The usual idea, you'll have to correct me if I'm wrong, is observation of an annual 'alignment' to winter/summer sol. etc., then construction of the monument on the correct axis? Could this be different; observation of one spectacular event and one monument to mark the same? Or how soon would something similar, with all those factors, be likely to happen? Though if, as you suggested, you're waiting 18.6 years for something you're not going to be able to see anyway...
That's what I'm thinking , visually similar even to the extent that it would proabably mean light entering the passage , after build . Never been too happy with minor standstills . It's all related to the Saros cycle which is like the standstills is an 18 and a wee bit years . Babylonians had that sussed 3 ,000 years later . 