Archaeo-optics in Orkney Day 2: First sunset at the Dwarfie Stane

At this time of year the chamber of the Dwarfie Stane opens towards the setting sun. We set up our equipment and waited.

There was heavy cloud overhead, but this was broken on the western horizon (Video still: Ronnie Scott)
 
Inside the chamber, the hills framing the sunset were clearly visible in the inverted optical projection. The glowing disc of the sun was also distinct whenever it broke through the cloud (Photo: Aaron Watson)
 
As the sun set further, the clouds remained broken. But there was never a clear view of the sun. (Video still: Ronnie Scott)
 
The sun finally set into a distinctive notch on the horizon. (Video still: Ronnie Scott)
 
Long exposure photograph capturing the moment of sunset as seen from inside the chamber. The image also includes the shadowed figure of Ronnie who was observing how light falls upon the outside of the monument (Photo: Aaron Watson)
 
The view across the roof of the Dwarfie Stane just after sunset.
 

Overall, a promising series of observations on our first day — and it was a spectacular sunset.