Wednesday, 7 November 2007

Pyramidal crystal halos

A funny coincidence that a halo-observer may want to experience is travelling to Egypt and seeing some pyramidal crystal halos.

This odd-radius display was photographed by Márk Laczkó of Budapest, Hungary somewhere over the southern borders of Romania. He was sitting on an airplane heading towards Egypt on 27th October. When he realised they were flying in cirrus clouds, he deliberately started looking for some halo phenomena. The surprisingly well distinguishable 18°, 20°, 23° and 24° halos were visible for about a minute at 06:21 UTC. Unfortunately, there is no documentation or report of a possible 35° halo. The original photo and two other pictures are also available (#1 and #2).


  1. Are these really halo's? It seems to me that the red color is on the outside-region of the arc and not in the inside-region.

    Couldn't it be just some interference in the window of the airplane???

  2. To my eye the colors are on the inside, assumung the sun in on the right. Nevertheless, interference fringes were my first thought as well. But upon looking at the non-encahnced images they just seem more like halos. It looks like the intensity variations follow the irregularities in the cloud.

    If we would know the angular dimensions of the photo field of view, that might help in resolving the issue. Ágnes, is there exif-data available?