Long story short: Mate of mine is a real, actual, bonafide Druid and has been working on a theory about ancient navigational techniques for years now. There's a big experiment when the lunar eclipse is on and he's looking for people all over the world to....well basically, look up when the moon turns red and mark what they see on a star chart using very, very low tech techniques like ancient man may have.

Details here: http://www.stonehenge-druids.org/science.html