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).

Odd radius display

12th August 2007 - This day I can see interesting halo display. I thought that I could see upper tangent arc and inexpressive 22 degree halo. But the upper tangent arc was more and more brighter and lower tangent arc has not been seen. It crossed my mind that this phenomenon what i can see isn’t 22 degree tangent arc but 23 degree plate arc. I searched another pyramidal halos, but didn’t see it. Through that I took some photo. When I stacked and adjusted this photo was seen 9° halo, 18° halo, 23° upper plate arc and 22° or 23° halo. Lukas Kosarek

More photos: Martin Popek, Nydek (2.7.) , Stepanka Kosova, Prague (20.8.) and Jiri Los, Prague (20.8.)

The Beginning of Halo Season in Hungary

The halo-season in Hungary has began in a very promising way. There were two particularly noteworthy displays this week. 

The first one was observed by László Henez "Felhőcske" on 16th September near Eger, Hungary. As a born halo-observer, even though he was quite unaware of what he was seeing, he took a picture of not only the sunward halos, but the anthelic side, as well, where about a quarter of the bright white parhelic circle was visible together with a Wegener arc curving downwards towards the anthelic point. The 22° halo and the upper tangent arc were seen in the sky covered with uniform Ci for about half an hour after 8:25 UTC, while the anthelic arcs for only a few minutes. László did not see any 120° parhelia or anthelion. More of László’s photos can be seen here.

In the afternoon of 18th September, an odd radius display appeared with pyramidal 18° and 9° halos besides the 22° one. The photo was taken by "Controll" in Jobbágyi, northern Hungary, but the 18° halo was seen in Budapest by Alex Farkas, too. The display started with a 22° halo and lasted for roughly 40 minutes, until 14:15 UTC. "Controll" reported that she had seen a possible 46° halo as well, but it was at the edge of visiblity. It’s worth having a look at the faint pyramidal crystal parhelia in the picture provided. The full-size photo is also available, together with a panorama image of the display.

Pyramidal halos 8-14-07

After weeks of seeing no nice halo displays I was at work today on breaktime and I saw 22 halo and upper 22 deg tangent arc. I put my sunglasses on and I soon realized I had an odd radius display at hand. In all there was 9 deg. halo 18 deg halo and the outer halo who knows it could be 22 or 23 or a combo of both. The upper arc is convincing it looks sharp and I think it might be 22deg upper column arc but not sure. One photo is an original and the other has USM applied to make the halos stand out better. This is a good odd radius display for me but I know there is a lot better.

Odd radius halo 6-19-07

While at work on break time I noticed there were cirrus clouds in the sky and I decided to check for halos and I got three odd radius halos which were 9, 18 and 22 or 23? degree rings. I took a few photos. I unsharp masked one of them the show the halos more clearly. This was probably the only halo highlight of June but nothing super special but it beats nothing.

Odd radius halos at Crete

These odd radii were a little bit surprising, I didn’t expect something like this at Asimenia beach in Kavroz. I had been waiting for any halos for five days and the first display was directly pyramidal 18°, 20° and 23° halos. Fortunately I had a piece of welding glass because photos I took without this protective glass was totally unusable because of reflections. The display originated at very thin cirrus clouds.

Martin Popek

Odd radii in Southern Finland

A horrendously quiet April passed by without any noteworthy action (except Jarmo's fantastic bolide halo). Halo people were awakened from oblivion on 5th May, when a smooth cirrostratus veil crept in from west and offered plate crystals and odd radii halos. The display was seen and photographed by Ismo Luukkonen in Turku, Marko Riikonen in Helsinki (photo on the right by Marko) and Jukka Ruoskanen in Riihimäki.

Most likely all odd radius halos were on the sky, of which 9, 18, 20 and 35 degree halos were easily discernible. The 22-24 region may have consisted of all three possible rings. Also few of the odd radius plate arcs were present, although rather poorly.

Odd radius halos in diamond dust in Finland

On 23 February an another diamond dust display with odd radius halos occured in Vaala, Finland. Temperature was dropping from -29°C to -24° during my observation.

A parhelic circle and circumzenithal arc were present with nice parhelia. A subsun and subparhelia were also seen as sparkling ice crystals in front of the ground.

Odd radius halos labelled in this enhanced photo are A) a pyramidal heliac arc, B1) upper 24° plate arc, B2) lower 24° plate arc and C) upper 23° plate arc.

The most brightest odd radius halo was 18° halo and in some photos there probably are also 9° upper plate arc and 20° halo. The ice crystal cloud was produced by a local heating plant about 2 km away. More photos can be found here.

Pyramidal heliac arc in Finland

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In 8 Feb 2007 an odd radius display was produced by local heating plant plumes in -28°C temperature in Vaala, northern Finland. I photographed this display on a road about 1.5 km away from the heating plant.

Odd radius halos in display were 18° halo, 23° upper plate arc, very faint 35° halo and rare pyramidal heliac arc. See arrows in a stacked and strongly unsharp masked photo shown.

Pyramidal heliac arc is formed by reflection from pyramidal side faces of horizontally oriented pyramidal ice crystal. It is usually visible near the sun only. It is usually very faint but this time I was able to see it also visually.

Same odd radius halos except 35° halo were also present in similar but much fainter display in Vaala couple of days earlier in 6 Feb 2007. More photos from both displays can be seen in Jarmo Moilanen's halo photo gallery or directly 8 Feb. 2007 here and 6. Feb 2007 here.

First odd radius halos observed 31st January 2007

While at work on break I saw some cirrus clouds gather in the sky and I later saw a halo appear so I got my camera out of the car and my sunglasses. As the minutes passed I notice that there were three halos: 9 degree halo 18 degree halo and possible 23 degree halo. The left side of the 9 degree halo looks strange because it is brighter on one side and has a somewhat vertical look to it.

When I later downloaded the pictures I went through them with adobe photoshop and I applied the USM and I noticed possible 20 degree halo and even a 35 degree halo! You can see at least 4 halos in the enhanced photo. The possible 9 degree column arc and 35 degree halo have been pointed out with black arrows.