I was in the Avebury 2012 formation the other day, and when I came to the Earth I was puzzled to find an off centre standing tuft, so small (about a foot) that it is virtually invisible in all the aerial photos.

 

I tried to take shots of it on the ground, but since I forgot to bring my camera pole (idiot!) I was unable to put the camera up high enough to get the entire Earth and moon in the frame.

 

But I DO have an aerial shot (which I had previously not even looked closely at because the aircraft's tire is in the frame) which is zoomed in enough to show the Moon (?) detail.

 

What intrigues me is that the tuft is off centre.  Given the unquestionable 2012 symbolism, if the dot was in the middle I'd say it just meant, "this is your planet."  But it's off to one side -- so I'm guessing the moon is passing over the Earth.

 

I wonder if your eclipse expert, "Red Collie" can make anything of it?  This might be just the clue that's needed to pin down the exact date.