Stonehenge Astronomy II: Solar Alignments

I assume I can talk about this now as it’s in the TV guides and mentioned at other places.

A television company making a programme for Channel 5 and National Geographic are building a 1:1 scale model of Stonehenge for the solstice. The plan is… Well the plan is to make a television programme that people would watch. What they’ve done is contacted a few archaeologists to see what experiments could be done with a life-size Stonehenge model. Clive was contacted, which was a bit of triumph in itself given how busy he is. Unfortunately Clive is scheduled up to his eyeballs so he’s away on fieldwork until the day of filming, so I’ve been working for him trying to set up some experiments. What experiments can you do with a life-size Stonehenge?

The model has been set up to align with the sun. We’ve given them details, but there is a slight problem. Which solar alignment do they want? Stonehenge has two. The one everyone knows is the summer solstice alignment.

Stonehenge Solstice 2003. Photo by Scottscapes

This is the one where the Sun rises over the Heel Stone at sunrise on the 21st of June. It makes a nice picture. It’s not exact though. There’s always a problem that photographers notice, that this year the alignment doesn’t quite work. Rather than standing at the centre, you have to stand a few metres off slightly to get the right photo. Usually this is explained by the Sun moving over the course of thousands of years. That’s accurate and entirely wrong. The Sunrise has moved slightly, but four thousand years ago the alignment was even further out. It’s a nice view, but is it the reason for Stonehenge? The model is set up to look this way because the programme transmits in the summer and if the summer alignment is missing then we all look a bit stupid. However we could be looking in exactly the wrong direction. The animation below shows the two alignments and where else we could be looking.

[FLASH]http://archaeoastronomy.co.uk/wp-content/images/stoneastro.swf, 500, 375 [/FLASH]The Solar Alignments at Stonehenge

If you approach Stonehenge from the north-east in midwinter then you would see the Sun set inside Stonehenge. This is arguably a more powerful alignment. Rather than just a few people seeing it happen, anyone approaching from the north-east would see it. Nice idea, but is there any evidence for this?

There’s an earthwork, called the Avenue by archaeologists, which approaches Stonehenge from this direction. The route uses the contours of the land to hide Stonehenge until you’re in the right position and then you climb a hill and it appears in front of you and, if it’s midwinter, the last rays of the Sun can be seen falling inside the circle.

I don’t know why Stonehenge was built, but you might want to think when you’re most likely to want the attention of the Gods. In summer when things are going well, or in winter when the air is cold and the Sun is moving ever further south. —–