The programme tonight was all about the moon alignments at Stonehenge. The whole 19 year cycle business is very clearly explained (I thought). You get to see some of (regular contributor) Pete Glastonbury's aerial photos. And they go to the Devizes museum to talk about the Bush Barrow artefacts, plus the real Lozenge (which isn't normally on show) - what a superb thing. And they mention the acoustic properties inside the circle too. (Though avert your eyes if you don't want to see a squillion people squashed into the henge).
No doubt on the iplayer imminently.