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).

From archives: odd radius column arcs in 2001

I saw this display in Oulu on 17 September 2001. Because the photos have not been around in the internet, I dare to make posting even though the event is not so recent.

The display has all the odd radius column arcs except the 23° arc. Images are stacked from 3-8 individual images. The one on the lower right is also flipped horizontally to get a bit more definition. For the upper left and lower images, simulations of the pyramid column arcs give crystals as in the figure. Also shown is similarly shaped real crystal, photographed during a weak odd radius column arc display at South Pole in 1999.

From pyramid plate crystals there is the 23° plate arc in all photos, and lower 9° and 24° plate arcs in the upper right photo. The display was discussed in more detail in September 2003 number of journal Weather. It also appears in the book "Atmospheric halos and the search for angle x" by Tape and Moilanen.