I felt strongly that there was once a post or stone outside the Sarsen circle at Stonehenge which lay between the Winter Solstice's SW sunset and the SW arc of the circle and cast a shadow on the 'fertility stone', which is how I interpret Stone 16.
(See links below for info):
http://www.megalithic.co.uk/modules.php?op=modload&name=a312&file=index&do=showpic&pid=36079
and
http://www.megalithic.co.uk/modules.php?op=modload&name=a312&file=index&do=showpic&pid=26301
and
http://www.megalithic.co.uk/modules.php?op=modload&name=a312&file=index&do=showpic&pid=54378
Here is a comment from a dear (sadly late) friend in Nov. 2008:
"My name is Alex Down - you'll remember me from [.. name of another website ..]. I hope you don't mind me approaching you directly, but [..] is having problems with comment postings, and I wanted to tell you about my experience at Stonehenge's Stone 16 at sunset last night, Wednesday 26 November.
I went there because it was a fine clear afternoon, with no cloud on the western horizon, the problem that bedevilled my last trip there. I wanted to test your theory that a post outside the ring to the south west could have cast a phallic shadow on Stone 16 at midwinter. Well, it's not quite midwinter (though it felt like it yesterday!) but, for astronomical purposes, it's close enough - the sun doesn't move far along the horizon around the solstices.
The headline news is that your theory works brilliantly. I'd wondered if the fall of the ground surface might have made it difficult, but 20 minutes before sunset my shadow reached most of the way from my position behind the barrier about 100 metres from the stone. (It's even further than last time I went.) It was a strong shadow; 10-15 minutes later, with the sun nearly on the horizon, my shadow reached all the way to the stone, though not so strongly. I took photos to illustrate the effect - unfortunately, I can't attach them here!
I think that a taller stone that was inside the ditch would have had a far more dramatic effect. And that now seems entirely possible. I'm reading Anthony Johnson's "Solving Stonehenge" and on p155 he has a short section entitled "Possible stone at southwest end of the axis." William Stukely reported that "there was another stone lying on the the ground, by the vallum of the court ...", Aubrey Hole 28 being the nearest. That sound exactly right, though it hasn't been confirmed by the geophysics survey in SIIL.
So a stone of, say, my height, at around 35 meters from Stone 16, would have cast a strong shadow up the carving towards sunset. And, as the sun set, that shadow would have advanced up the carving in a highly symbolic manner, if you see what I mean."
(I have his photos, and went there on 17th December 08 [?] to take my own, with a positive result.)
I first met up with Alex in person after sunrise on 21st June 2009 and we further tested this theory by my dowsing for a possible post and photographed Alex standing on the spot where the rods indicated it had stood. Alex also plotted this position on computer, and I have the result in my own files.
Something is not right. This message is just to keep things from messing up down the road