Circumzenithal Arc

The circumzenithal arc may be seen on its own with no other halo effects apparent. If the cirrus is extensive enough then sundogs are often seen, if there is a mix of crystals types the 22 degree halo may also be visible. The huge range of brightness makes it difficult to record colour and detail in sundogs at the same time as the circumzenithal arc.

On this occasion the 22 degree halo was visible and this image shows the relative positions of the two haloes. Although it wasn't particularly bright the colours in the circumzenithal arc were noticeably purer than the 22 degree halo.

The remains of a broad and colourful circumzenithal arc are at the top right. A rather fragmented 22 degree halo sweeps round to a bright sundog at lower left.

Other Halo Topics