This stream of cirrus produced a bright circumzenithal arc which lasted for several minutes.
The uneven cloud meant that the colours were fairly patchy and the arc wasn't complete.
A very weak upper tangent arc could also be seen briefly well below the main arc.
Another colourful arc in a patch of cirrus cloud.
The cloud where the upper tangent arc would have been was lower down in the atmosphere. It was probably water vapour, not ice, so it didn't show halo effects.
Other Halo Topics
© Richard Fleet 2004-2008