Luleå, Northern Sweden 21st December '06.

David Legge took this image at 2:53pm. The sun was 7° below the horizon having set at 1:10pm.

The nacreous clouds are so high in the stratosphere that they still catch the sun's rays.

Thw fainter clouds at extreme left show the vertical wave structure of these clouds that is not usually so apparent from the ground.

Image ©2006 David Legge, shown with permission.