Clip two: Observations of the action of the sun at Mousa broch on 21st June 2009. The video and accompanying photographs document the movement of an arced shadow travelling down into and across the internal walls of the broch.

07.50 am: void set A
07.50 am: top of broch
11.40 am: entrance to broch with voidset A and entrance to Cell A (on right)
12.00 noon: entrance to cell A, up and right to void set B, then left to void set A, down to broch entrance and entrance to cell A
12.27 pm: void set B, then left to void set A, down to broch entrance, then right past entrance to cell A towards entrance to stairs
1.30 pm: entrance to stairs and void set B
2.00 pm: entrance to stairs (left) and entrance to cell B (right); lastly inside entrance to stairs.

Figure 28 Figure 33 Figure 34 Figure 35
Figure 36 Figure 37 Figure 38 Figure 39
Figure 28: View from the top of the broch at summer solstice 2009.
Figure 33: Sun penetration entrance at 11.48 am. Broch entrance at bottom left of photo faces West
Figure 34: At 11.50 am showing top of voidset A and shadow of opposite wall head illuminated
Figure 35: Sun penetration 12.00 pm. The sun continues its progress south and illuminates an area on the wall at the base of gallery 1, directly above Cell A
Figure 36: Sun penetration 12.50pm. The sun continues south and illuminates an area on the wall below the wall base, between cell A and small cell to left and below the stair entrance
Figure 37: Solstice sun over stair entrance. 1.48 pm
Figure 38: 1.38 pm Illumination of cells next to stair
Figure 39: 1.00 pm to 2.00. pm Sunlight enters stair entrance illuminating the inside of the doorway