I have written some thoughts on halo naming.
Google Docs:
https://docs.google.com/document/d/1wCHmYaO5bZHeeQH-uEhWV51xBj1i_oPDAtoWKbxrm0o/edit?usp=sharing
PDF:
https://drive.google.com/file/d/1X0pdvkEwQJFwNS6zBpOpWiVAnMTaFLkE/view?usp=sharing
Marko Riikonen
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| ©Marko Riikonen |
The Rovaniemi Display of November 11, 2023 – possibly one of the greatest and most bizarre Super Displays ever – a sentiment Marko and I both share. I was deeply fascinated by it when Marko first posted it.
https://www.taivaanvahti.fi/observations/show/119911
https://x.com/RiikonenMarko/status/1871867455959707898
Above are the original publication, along with additional photos and simulations uploaded by Marko at the end of 2024. In private correspondence with me, Marko mentioned that the identification of the 24d Column Arcs came from a suggestion by Nicolas Lefaudeux. The previous work of Nicolas and Marko has already addressed the simulation for most of the halos observed in this event.
However, previous simulations failed to match some halos in the photographs – for instance, the peculiar '35d Spot'. Some of the mysterious puzzles revealed in this event still require further exploration by halo experts and enthusiasts.
'35d Spot' is not at 35 degrees !
Ice crystals that produce 24d Column/Plate Arcs theoretically also produce 35d Column/Plate Arcs. But the problem is that the so-called '35d Spot' observed in this event does not align with the theoretical positions of 35d Column/Plate Arcs – it is clearly much closer to the light source.
Precise measurements show that the inner edge (closer side from the light source) of the '35d Spot' is about 32°, and the outer edge (farther side from the light source) is about 38°. Obviously, based on measurement result, they are not 35d Column/Plate/Parry Arcs. Some other types of halo must be present and is the main contributor to this strange bright paire of spots.
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I also tried exotic pyramid crystals (Miller indices: 3 0 -3 2, 1 0 -1 2, 2 0 -2 1, 2 0 -2 3, 3 0 -3 4, 2 0 -2 5, and 1 0 -1 3), but none provided the correct answer. Perhaps the approach using exotic pyramid crystals was wrong from the start, because even if some special crystals that haven't been found in atmospheric samples can form 32° radius halos, it would be difficult for us to ignore the other halos that would accompany them.
Despite many failures, I have recently found a better answer – The 22° Parhelia of the 22° Column Arc.
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The first record of '22° Parhelia of the 22° Column
Arc' ?
Multiple Scattering(MS) halos from 3-5 ray paths will be closer to the light source than 35d Column/Plate/Parry Arcs. However, differences in the order of 'the first/second type of crystals' can lead to different halo manifestations. I tested various combinations, and ultimately concluded that only the '22° Parhelia of the 22° Column Arc' provided the best match. The '22° Column Arcs of the 22° Parhelia' were ruled out due to unsatisfactory position and shape. MS halos related to the Parry arcs were eliminated because they were too sharp and also ill-positioned.
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The second scene taken by Marko also supports this conclusion. In this scene the camera pointed towards the zenith, and Marko had stacked the images, which is more conducive to revealing the ideal morphological characteristics of halos than a single image.
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Precise alignment work showed that the '22° Parhelia of the 22° Column Arc' once again performed very well. This time, even without the contribution of 35d Column Arcs, the '22° Parhelia of the 22° Column Arc' alone aligned the shape/position of the '35d spots' in the stack-image very well.
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So, did Marko capture another Borlänge Arc?
No. I suggest that the situation in Rovaniemi on
Previously, on Taivaanvahti or TheHaloVault, the Borlänge Arcs were defined as a combination of both the '22° Parhelia of the 22° Column Arc' and '22° Column Arcs of the 22° Parhelia'. This conclusion is likely based on simlations in Halopoint. However, this might be incorrect.
https://www.taivaanvahti.fi/observations/show/79745
https://thehalovault.blogspot.com/2018/12/complex-halo-display-borlange-sweden.html
After using Zhang Jia Jie's program for further research, we can see the differences – the position and shape of the MS halos in Borlänge and Rovaniemi Displays are not the same. In the Borlänge Display, people likely only observed the '22° Column Arcs of the 22° Parhelia', with the '22° Parhelia of the 22° Column Arc' either not being a major contributor or not appearing at all.
A similar conclusion applies to the
Naapurinvaara Display in
https://www.taivaanvahti.fi/observations/show/95033
https://thehalovault.blogspot.com/2020/12/two-years-ago-halo-community-got-its.html?m=1
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I'm unsure if there are other records of Borlänge Arcs around the world. The halo community can help verify this. If there has been no prior confirmed record of the '22° Parhelia of the 22° Column Arc', what Marko captured may very well be the first record of this phenomenon.
A proposal to redefine the
Borlänge arc
It was previously widely believed that both of the '22° Column Arcs of the 22° Parhelia' and the '22° Parhelia of the 22° Column Arc' should appear together, which if why the Borlänge Arcs were defined as a mixture of two halo phenomena. But now, should we consider the case of 'only one of them appears alone' – in such cases, they no longer fit the name 'Borlänge Arcs'. Jokingly speaking: a rock band typically has 3, 4 or 5 members; when one member appears alone, they cannot be fully equated with the entire band.
So, what should the new name be? Riikonen Arc? - that name has already been used for another halo. Perhaps Rovaniemi Arc is a name worth considering, or perhaps we should strictly name these MS halos according to their ray paths? In any case, Marko told me he has an article on halo nomenclature ready for publication, perhaps we will find better solutions for above discussions in his article.
A strange spot appeared on the inner side of the right 22° Parhelion. Obviously, it was not any odd radius halo.
To me, the reason for this phenomenon is the diffraction and interference of light. The USM images seems to support this speculation.
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These rare images were taken by ZHANG Jin Rong from the Chinese sky enthusiasts' community (in BeiJing, on January 1, 2026, from local time 15:50 to 15:56).
Several years ago, when the "multiple CZA" was discovered, it was also considered extremely rare. But nowadays, at least dozens of people around the world have captured the "multiple CZA". Perhaps, in the near future, more diffracted 22° parhelia will be recorded. Now I'm already looking forward to the discovery of the diffracted CHA. Anyway, what a crazy New Year gift for 2026!
The sub-Liljequist 'Parhelion' in high-clouds is rare. On August 14, 2025, a user '太平洋蓝藻'(ID: 516836436) from ' Bilibili.com'(a polular vedio website of China) captured the first record of this event in China during a flight over the Yellow Sea. the sub-Parhelic Circle and sub-120° Parhelion were captured at the same time.
What makes this particularly remarkable is that on left of sub-Liljequist 'Parhelion' in the photograph shows a distinct blue tint, suggesting the possible presence of 'sub-Liljequist Blue Spot'. Pinson HUANG from the Chinese halo watching community was the first to identify this possibility and made the initial simulations. I refined the simulation parameters based on HUANG's work, and the results showed a good alignment with the photograph. SUN Hao Xuan(孙浩轩) and Jing Xiang from the Chinese halo watching community assisted in image authorization and joined in the related research process. KiloNova(千新星), SONG Xi Pei and QIAN Kun from the same community provided crucial information in the analyses of flight data and lens characteristics.
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USM.jpg)
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The photograph was taken at 16:43:26 (UTC+8). Based on the CZ5855's flight information(N37.96, E122.98) retrieved from https://flightadsb.variflight.com for that specific time, it can be further concluded that the solar altitude was 22.3 degrees.
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| The unevenness of cloud layer should be considered as the cause of the unevenness of the sub-PC, but some simulation results quite support the existence of the sub-Liljequist. |
South America is pretty much a blank slate what comes to halo enthusiasm, so it is encouraging when we got contacted from Venezuela by Franklin Fernández, who had written an article presenting the best displays captured in his country. Judging by the random big displays that have popped up from different corners of South America over the years, there is reason to think the continent as one of the better areas for halos, and now the Venezuelan displays Fernández has scoured from the internet add credence to this notion.
What is more noteworthy is that the best displays are concentrated in the western part of the country which is where the Andes mountain chain ends. This gives more weight to what some of us may have already thought, that the curse of the equator is cancelled by the Andes. Unlike in the Philippines where I have been observing, or Singapore of which halo scene I have heard from Jia Hao, all-sky displays must be a regular occurrence along the tropical segment of the Andes chain and presumably sun pillars are not such rarities either. And we don't know what kind of odd radius jewels there might be lurking as these shows don't tend attract so easily the attention of the uninitiated.
Franklin's article is available in Academia.edu and Scribd. He will keep adding displays to it as they come and says the document has already created buzz. Could this be the start of Venezuela and eventually the continent's other Spanish speaking countries waking up to halos? All prospects are that a dedicated observer, in particular along the Andes chain, would be in for reaping it big.
(The display above was captured by TikTok user danny3461 on 6 October 2024 in Macoa near the city of Machiques at the west of the country. In my hastily made stitch the parhelic circle is full despite the large gap on the right. The show was documented by a handful of other people as well. See also the impressive high sun display on X of an unknown date in Caracas)
A spectacular
event of Bottlinger's Rings occurred on January 12, 2025, in Hemu(禾木),
Xinjiang, China. For
Footages show a solar elevation angle of 11 to 12 degrees. The lack of ice crystal sampling
is regrettable, and it is hoped that valuable ice crystal samples can be
obtained the next time such event occurs.
The original web link: https://www.bilibili.com/video/BV1jKKweuEQG/?share_source=copy_web&vd_source=e
(We'd like to
thank: Sufflection_, Jingxiang and Danyang(佩佩), for their
assistance in related communication.)
Every year from March to May seems to be the pyramid column arcs' season for China. In the 2024 season, the most eye-catching display occured on 6 May, ChangSha, HuNan Province. At altitude of about 71.3°, the Pyramid column arcs, PC and Wegener crossed each other, bringing a spectacular picture of the sky.
