Odd Radius Display, Southern Ohio, USA, 17th August 2019

On the evening of Saturday, 17th August 2019, I observed this complex pyramidal halo display. In total, I saw a faint 9d halo, lower 9d plate arc, bright 18d plate arc, 18d halo, upper and lower 24d plate arcs and a weak upper 23d plate arc. This display is very similar to the one I captured in 2017, the only difference being the one in 2017 the lower 9d plate arc was bright and colorful and in the present display it was weak.

Pyramidal halos 7-10-19

Before leaving for work yesterday, I saw some cirrus clouds moving in and in a short time later 18 and 23d halos along 18d plate arcs, and bright upper 23d arc appeared. The display went on for a while and when the sun was high enough, a bright and well-defined lower 23d plate arc formed. The lower 23d plate arc in this display is my best to date.

Odd Radius Display, Bolton, United Kingdom

On the 5th April 2018, there was a short lived but rather nice odd radius display in Bolton, a town situated in the north west of the United Kingdom. As I was preparing to go to work, I noticed the top of what I initially took to be a 22d halo. However, it rapidly developed and became more complex and very soon an 18d became easily visible to the eye. The display lasted about thirty minutes in total and I was only able to take a few single shots and a couple of stacks before it began to fade and I had to leave. Upon processing the images, 9, 18, 23, 24 and 35d halos with attendant plate arcs were identified as being present.

Processing courtesy Nicolas Lefaudeux.

Pyramidal Crystals Attacked Hungary

Photo by: Károly Tuszinger - Budapest, Hungary (single frame)

Despite the government’s efforts to stop “invaders” at the border, a lot of pyramidal ice crystals could penetrate our homeland on the 3rd of April. At least 3 legions of them rushed across the country arriving from West and reaching the Eastern borders late in the afternoon. The attack had left a lot of people with severely high adrenaline levels – and a lot of excellent photographs! 

 

Photo by: László Dombai - Vép, Hungary (single frame)

The first signs of the display appeared at early dawn when a vivid circumscribed lunar halo formed with some moondogs, faint CZA and easily visible, still faint supralateral arc. In some pics an extremely faint 9d halo was noticed later (I could not see it while being outside). Then after sunrise in the early morning, parts of 18d arcs were visible, probably they were 18d parhelia, but this only lasted a very few minutes and they were also faint. For some hours nothing happened, then at noon another pyramidal crystal containing cirrus arrived and caused a fine display at my place which lasted for about 20 minutes. 9-18d halos were well visible and also the „22d” halo’s arc was too broad to be a simple 22d halo. I took some pics around, but 35d was not present. In the meanwhile the clouds drifted towards East, they were on their way to Budapest and the surrounding area where a lot of people could observe and capture the best of the show in the afternoon. This region had received the elite commando of the pyramidal legions, with an extremely vivid display; the arcs were easily seen even on the worst quality weather webcams’ images! Webcam videos of idokep.hu: Fót and Hajdúszoboszló, Hungary. 

A decent full circle 9d halo with colourful 9d parhelia appeared on most pics, the full circle 18d halo with vivid 18d parhelia was also present, 23d full circles with some cases of 23d upper parhelion (or at least the arc’s colour was much more vivid at the location of the 23d upper parhelion). One wide angle pic shows signs of a very faint 35d arc too. The show lasted about an hour (at least the N parts of the capital). Then the clouds drifted on towards the East and caused a less spectacular but still fine display late afternoon. The northern half of the country was affected by the display or at least parts of it during the day. 

35d halo on the single frame image of Péter Lenkei from Ötschergraben, Austria

Of course this is the case when stacking would lure out more detail, but most people just rushed out from their workplaces to capture the rarity with their cellphone cameras, still the beauty of the show was that even without stacking many details were visible.

I guess it was very lucky that the clouds had done their best in the Budapest area where most of the population concentrates, so many observers could capture the show. I can’t remember any similar case of pyramidal display in Hungary in the past 20 years, it was so vivid, so widespread and so complex!

By: Mónika Landy-Gyebnár

Pyramids returned and came with multiple plate arcs

The halos I got earlier today ended at midday but while up mowing the ATV and foot trails I saw halos reappearing! I immediately saw a nice bright lower 9d plate arc my second one since 2002 and both lower 24d plate arcs my best to date! As the clouds moved in closer the halos got better the 18d plate arcs got bright and rather colorful and actually showed a slight curve. At 7:00PM when the sun got low enough for it to happen I got upper 9 and 24d plate arcs and those were two new halo forms for me.

Reign of the Pyramids

Well seems like most of the rare halos I have been getting are pyramidal this year and I like pyramidal stuff. This morning I got up and later on 18 and 23d halos formed along with a nice upper 23d plate arc and 18d plate arcs. Later on faint 9d halo and when looking at the convex mirror faint 35d halo and it shows up in Photoshop.

Odd radius plate display in Czechia

On June 4th a cold front was advancing towards Czechia with thick Ci/Cs cloud cover ahead of the front.
Zbyněk Černoch was keeping an eye for any potential halos that might show up. As soon as the cloud cover started to sublimate (it was nicely visible on satellite imagery), bright pyramidal plate arcs showed up. The 23° parhelion is very easily distinguishable with its characteristic shape.

A few moments later, the 23° parhelion lost its initial shape, but became a little more coloured.

The same photos, with B-R processing:

The all-sky display of 30th May 2017 at Pskov Oblast, Russia

08-09

The first part of this display occurred between 6-50 and 8-30 hours. During this period only the 22 halo (which accompanied by other common halos in stacks) were seen in this part of the sky. However, at the end of this period a wonderful cloud crossed the sun. This cloud gave a complex of rare halos from Parry and Lowitz orientations - on the stack I found the sharp and bright upper suncave Parry arc together with the upper Lowitz arc. I saw a part of the middle Lowitz arc, which was below the right parhelion, with the naked eye (1).

Thereafter, cirrus clouds cleared, and in satellite images no high-level clouds were visible, so I went to a bicycle training although the meteogram would predict the arrival of a new portion of cirrus in the coming hours. If I had looked at sat24.com during my training, I could have seen that the air ahead of a low-pressure system after passing the Baltic sea, created fresh cirrus clouds above Estonia!

At 15-40 I found that far cirrus clouds which were visible for the last hour at the horizon, now reached the sun. At this moment I saw a colourful lower tangent arc. It was only 5 km to my house , so I accelerated in order to be in time to photograph it. However, a few minutes later I saw a large scale complex in the sky - above the sun there also appeared an upper tangent arc, both parhelia, and a full parhelic circle! The last few kilometers I rode as fast as I could. Luckily, I not too late!

16-17. All three Lowitz arcs are in one image. The B-R version is available here

Visually, it seemed to me that the bright parhelic circle contained a red fringe, which also surrounded a diffuse 120 parhelion. Blue minus red versions of some stacks clearly show this diffraction effect (2).  The cirrus clouds were beautiful, they contained not only a smooth veil, but also sharp textures like virga. What they are fresh was seen with the naked eye.

16-37

After half an hour, the bright parhelic circle disappeared, when clouds which produced it, drifted to the south-east direction. The upper tangent arc then started to get brighter. At this time I also saw visually both the infralateral arc and the 46 halo above the sun from the 11-00 to 01-00 positions. The complex became less bright after one hour, but at the same time, fragments of a distant parhelic circle was still visible.

17-08

Thereafter, I could see only a split upper tangent arc. With the naked eye I could not understand what it is - a Parry arc or a 23 plate arc. The stack taken during this period showed an excellent odd-radius plate complex!

Recent displays from Northwestern Russia

In this post I want to share some of my observations from last month, which I made in St Petersburg (from 15th April to 5th May) and in Pskov Oblast (from 7th May to present time). In total there were eleven displays, six of them comprising pyramidal halo forms. Many of these pyramidal displays were minor, so I will not present them.

20th April

The photo on left shows a purely odd-radius plate complex. There are only the upper 23 plate arc with its 23 halo and a couple of 18 plate arcs. On the photo on right you can see fragments of weak odd radius circular halos. Together with the broad 22 halo at the 02-00 position there is the 20 halo and also the diffuse 35 halo.

28th April

Together with classic halo forms in stacks pyramidal halos appeared with odd-radius plate arcs. On photos above you can see lower 24 plate arcs with the 24 halo and the 9 halo (with possible the lower 9 plate arc). The weak and diffuse upper 23 plate arc is also available.

30th April


In the morning there was a short display which lasted less than one hour. The display was not predicted by the meteogram, so maybe I missed most of the display, which was earlier that morning. In any case I saw bright parhelia with the colourful circumzenithal arc, and got in the stack the strong parhelic circle and the upper suncave Parry arc together with the nice upper tangent arc. I think it is the Parry arc, and not an upper 23 plate arc, because the display does not contain no other pyramidal halo forms, and the arc looks pretty sharp.

1st May

In the morning I observed the large and bright upper tangent arc for around one hour. Infralateral arcs were easily seen with naked eye. Together with bright parhelia I saw fragments of a parhelic circle. In stacks the rare Wegener arc was found.

5th May

On that day there was a protracted display, that lasted between six and sixteen hours. But my camera had recorded interesting halos only at the start, on the sunrise. It was an odd-radius circular complex which contained pyramid halos with radii 9, 18, 24 and 35 degrees. It seems the 24 halo included rudimentary upper and lower 24 plate arcs.

10th May

No rare halos on that morning but I saw the supralateral arc visually very well, that happens not often. A curious circumzenithal arc appeared a little later. The CZA was diffuse, that is not typical for this halo. 

The Salzburg halo

On the 19th October 2013 Zbyněk Černoch was in Salzburg keeping an eye for halo events, since high cirrostratus clouds were rolling in. As they drifted towards the Sun, he first noticed bright parhelia. A few moments later, rather bright and colourful upper tangent arc with Parry arc and upper Lowitz appeared.





What stunned him later was a vivid arc similar to a parhelion, but located in the 18° region.



The arc lasted only a few minutes as the clouds were drifting away quickly. He haven't seen anything like this before.

After a few discussions the observation fell into oblivion. Until few days later when we thought we would like to figure it out once and for all.

It would seem that the arc itself is a fragment of 22° halo, but the halo itself was quite sharp and narrow in this observation.

After Zbyněk put together 3 photos to show that the 22° halo lies between the mystery arc and 22° parhelion, I decided to run some simulations.

I used pyramidal crystals with std of 15° in the c-axis and joined the simulation picture with the collage from Zbyněk.



My theory is that the mystery arc is actually an 18° plate arc. But there are some inconsistencies in the theory.

1. The color vividness indicates that oriented crystals formed the arc. However 18° plate arc formed by oriented crystals has a typical convex shape which is absent here. 
2. By increasing the std in the c-axis, halos from poorly oriented crystals are becoming more apparent, which is not the case here. 
3. No other odd radius halos were observed. 

If it really is a case of an 18° plate arc, it is a really decent one.

A spring-starter in Finland

On 25th March a relatively small high-cloud area swept over Southern Finland and produced a fine halo for observers in Helsinki, Espoo, Turku and Riihimaki. In Riihimaki the upper Lowitz arc was continuously in the sky for over three hours. In addition to Lowitz, there were also pyramidal crystal halos (9 halo/column arc?, 24 lower plate arcs, 18 plate arcs), helic arc and Wegener anthelic arc.

The photograph above is taken by Jukka Ruoskanen, and more photographs can be found here. In Helsinki the display was photographed by Marko Riikonen, in Espoo by Panu Lahtinen and Timo Kuhmonen and in Turku by Ismo Luukkonen

By Jukka Ruoskanen

Circumscribed halo and pyramid halos in Sardinia

This display was captured by Jan Drahokoupil in Sardinia on 6. September. The 22° halo is surrounded by elliptical circumscribed halo. The small halo around the sun is 9° halo or 9° column arc (or both together). Simulations could give better clue. Later on the display changed and there were also 18° plate arcs.

More photos here.