This was the basic setup of the final test configuration (East Sussex, 06, 2013): This apparatus (photos below) shows how the sun revolves around the world if you thought that the world was fixed at the centre of the Universe: This is a simple form of spherical solar concentrator (similar to the "Solar Oven" at Auroville, India). I just used bamboo for the perimeter ring because I was worried about damaging the field. I've used a small mirror set and a reflector which splays the light out more, so isn't quite as bright as the old one:
I didn't go for the 'summer set' in the end, so the reflector is a bit low relative to the trilithons. Here's the setup working: The mirrors were a little out of focus at the time, but it shows the arrangement:
Most interesting thing is that I'm finding out stuff I didn't know. The lozenge shaped reflections on the inner face are useful: Because the inner surfaces of the Trilithons have been worked to be flat, you can use the reflections to see if the mirrors are focused rather than having to eye-in all the mirrors from the hinge.
It's a much easier way than I had been using. But it needs flat worked surfaces so I doubt there's a commercial application to today's comparable systems.
PS I forgot to say why I've put all this up: Had a Professor of Archaeology (and an expert in Stonehenge) write to say he agrees that it was a working model of their Universe. Also will be demonstrating it to an archaeological forum, who've asked to see it running. Recent Stonehenge books have poo-pooed the idea of the Druids being involved in Stonehenge on the basis that Druids were Celts and the builders of Stonehenge were an earlier period. However, I can't see how the history & knowledge would not transfer through to the Celts, perhaps even in its entirety. I thought that seeing this might be of interest to the Druid community but haven't got much feedback so am not sure.