Hello everyone,
after several talks with Alec, I decided to make some digging into my old odd radius halos displays to search for rare halos and find out some more 28d halo (and 13d halos too).
Here are some examples of what I found so far that might be interesting to submit here to your assessment. I hope you will find those cases interesting.
For some of them, I still have all the raw files of the sequence, for others, I kept few raw images, but for all of them (exposed here at least) I made various time-lapses to keep sequence in B-R rendering, colour rendering, stacked with 4 or 8 images each, like the one I presented earlier in this blog.
I will start with a sharp display of odd radius circular halos I got last year, in April, at the morning.
I'm not usually an early bird so I can miss some nice displays each year. For this one I got the chance to have the display still available to start a capture from my roof window. The center of my house is a stair tower which offer a nice blocking roof for the spot I am from. Therefore, with the shaprness of the display, the 9° ring was particularly well visible on B-R rendering before the sun comes out of the roof (because the diffusion of the light on the lens add noise up to the 9° ring area).
There is a first image, B-R rendered from a sole raw image, to give a view of the sharpness of the event:
Stacking with the above one as first image, with the 25 following images makes those odd radius halos more clear:
Well, in the light of recent search for 28+° ring, this was one of my first tries even if I was expecting, like for the 13° halo, to find it when the rings are not sharp. But if you don't try, you won't find anything.
So there is a processing the the previous stack to enhance sharp halo first then eventually larger borders ones if any.
There is a folder on my drive, so you can take a look at the time-lapses of the day. As usual, better download it rather than viewing it as a Youtube video, to have a better video compression (as is the original one)
Many years ago, I got a nice odd radius display at sunset, during a day of November 2014. The view is not ideal, as I placed my camera on the edge of a window, look south, with a wide angle rectangular lens, hence the distortion. (EoS 1200D + Sigma 8-16mm, set at 8mm).
I was so amazed by the display I sent it to Nicolas Lefaudeux to have his expertise on the matter. And then he told me I caught the 28° halo, again (but I don't recall why this 'again') ;-)
There is the display, B-R rendered, and unsharp masked.
Unfortunatly, I did not keep any raw file of this event.
There is a folder where are all the remainings.
And any old how, here are some I cannot say it is, but looks like there might be something there.... or not:
And while browsing at all of those, I realized I got at least a dozen of 13° halos, with at least one with the Moon. Which could make a post after this one, for the record.
And a last one, not for the 28d spotting, but only because I like it a lot:
Now, a couple hours after starting this post, I think I may go get some rest ;-).
Greetings from France.
Nicolas R.
Showing posts with label 23° plate arc. Show all posts
Showing posts with label 23° plate arc. Show all posts
Thursday, 18 May 2023
Saturday, 22 December 2018
Some odd radius column displays from China in 2018
Odd radius column arcs have long been deemed as some of the rarest halo forms. Sighting reports in most parts of the world have indeed been sparse. However, during the past few years in China, we came across a good number of odd radius column displays. Spring monsoon seems to bring them to our country every year.
In 2018 we documented at least a dozen such displays country wide, most of which occurred in April and May over Southern China. Here I’d like to share with the world some of the most noteworthy ones. All photos below are single shots with only minor USM applied.
On April 29, photographer Cui Yongjiang witnessed a long lasting display from Shangri-la, Yunnan Province. Complexity of the display peaked in the afternoon when the sun dropped to around 40° altitude. The 9° and 24° column arcs in this display are rather weak, implying short prism faces among the crystals.
 |
| © Cui Yongjiang, shown with permission |
Later on May 17 in Sanya, Hainan Province, Weibu captured a short-lived display in which the sun sit at 83° altitude. At such high altitude, most odd radius column arcs turn into circles. The 20° and 35° column arcs have their upper half much brighter than the lower half. The way that the 20° column arc completely outshines other arcs in this display is quite interesting. Crystals with long pyramidal caps and very short prisms might have been responsible for such appearance.
 |
| © Weibu, shown with permission |
Up until August, all documented column displays took place in Southern China. Such displays have been much rarer in Northern China where monsoon from the Indian Ocean hardly reaches.
The pattern does get busted sometimes. On August 12, the best display of the year swept across Heilongjiang Province in Northern China. Middle school teacher Mao Xiufang from Daqing noticed this complex display during class break and snapped this amazing shot with her phone. The 20° column arcs in the display are sharp while the 35° column arcs are vividly colored. The 9° column arcs are even displaying their theoretical curly-bracket shapes.
 |
| © Mao Xiufang, shown with permission |
An hour later, the clouds advanced 200km east with crystals reaching their peak diversity and optical quality. Fang Tongbing grabbed this handphone photo manifesting the display at its best. The sharpness of the 9° , 20° and 24° column arcs are very close to simulations. Had the crystal quality been any better, we might even start seeing traces of odd radius Parry arcs!
Apart from the column arcs, some plate orientated crystals also joined the party contributing to a weak 23° upper plate arc.
 |
| © Fang Tongbing, shown with permission |
This high quality display turned out to be the last odd radius column display from China in 2018. Overall we had a big year for odd radius halos. Interestingly all these displays occurred close to noon hours when the sun was higher than 40°. The cause of this pattern could be a meteorological subject worth studying.
Hopefully in the year of 2019 we will be blessed with more displays like these. Stay tuned.
Jia Hao
Friday, 14 April 2017
Recent displays from St Petersburg, Russia
In this post, I'm including the most interesting displays observed during the last month.
14th March 2017
On that day, halos appeared in the morning in separate cirrus clouds. Their arrival was not predicted by the meteogram. When I looked out from the window, I saw a bright CZA, but when I came down, it had disappeared. Nevertheless, I could see the weak supralateral arc. Half an hour later, I also saw a nice infralateral arc, when the cirrus cloud reached the horizon.
29th March 2017
In the evening bright parhelion was detected, and then a little while later also the wide circumzenithal arc. The halos were produced by the anvil of a convection cell.
14th March 2017
On that day, halos appeared in the morning in separate cirrus clouds. Their arrival was not predicted by the meteogram. When I looked out from the window, I saw a bright CZA, but when I came down, it had disappeared. Nevertheless, I could see the weak supralateral arc. Half an hour later, I also saw a nice infralateral arc, when the cirrus cloud reached the horizon.
29th March 2017
In the evening bright parhelion was detected, and then a little while later also the wide circumzenithal arc. The halos were produced by the anvil of a convection cell.
1st April 2017
In the morning, at 10-00, the sky was clear. But in the south-west direction, low over the horizon a lot of cirrus clouds were visible. Their arrival was extended for an hour and a half. When a border of a front of cirrus clouds started to arrive, I noticed that it was weak and almost transparent. When these weak clouds reached the sun, at first I did not notice any halos. But soon, some markers of sub-visual odd radius display appeared.
It was broad and undefined halo in 22° area, with pretty obvious upper 23° plate arc in some moments. In the reflection of my sunglasses these things were visible a lot better. These weak odd radius halos were visible for around a half of hour, or even more while the area of weak cirrus crossed the sun.
Then, on the right-hand side pretty bright 22° halo started to appear. It was the arrival of main part of cirrus. In that area clouds were common and solid. After few minutes both bright tangent arcs appeared. Lower tangent arc was brighter than upper. I also noticed big infralateral arc on the right-hand side. It was pretty weak, but well coloured. I could see the arc better when I used peripheral vision.
This peak of the display was rather lengthy, and during its course I also watched both 120° parhelia, parhelic circle (it was easily seen within 22° ring), and the top part of 46° halo (likely it was the combination of supralateral arc and 46 halo. Although both were weak, together they became visually visible).
The peak was interrupted when middle-level cloud started to arrive. Then I saw a couple times only bright 22° halo
7th April 2017
The display looked quite ordinary, so I was glad I detected pyramidal halos such as upper 23° plate arc and 9° column arc.
9th April 2017
On that day, there was only a weak 22° halo. But the stack discovered also 18° halo/18° plate arc
10th April 2017
It was the weak display, which lasted most of the day. There was no suspicion that there may be pyramidal halos. But still I got upper 23° plate, 18° plate arc and 9° halo in the stacks.
9th April 2017
On that day, there was only a weak 22° halo. But the stack discovered also 18° halo/18° plate arc
10th April 2017
It was the weak display, which lasted most of the day. There was no suspicion that there may be pyramidal halos. But still I got upper 23° plate, 18° plate arc and 9° halo in the stacks.
Wednesday, 24 February 2016
Lunar odd radius display in diamond dust
On four out of last five winters Tapio Koski has photographed lunar diamond dust odd radius halos in the Rovaniemi area. These one-per-winter occurrences are almost solely responsible for lunar diamond dust odd radius displays photographed in Finland during those years. This winter we wanted take part in the tradition. Yet despite numerous odd radius displays we had harvested in the beam, those by the moon – or sun for that matter – were simply not coming.
Except on the night of 20/21 January, which was the month’s last diamond dust night in Rovaniemi. During the day, when driving in the city, we paid attention to Fairbanksian amber, a beautiful yellow glow in the sun direction that can be seen in cold weather and with which we became familiar on the successful halo expedition to Fairbanks in January 1996. This gave us an omen of foreboding that a night of big odd radii diamond dust was finally on the cards for Rovaniemi. Weather forecast was with us too, as the temperature was expected to drop to -33° C – the magic number that Walt Tape has given as being in the centre of the temperature range favourable for odd radii.
The display appeared as some thin water cloud that had momentarily overtaken the sky cleared away. The first halo visible was upper 23° plate arc, many others soon followed the suit. In the beam only a crappy plate dominated display was visible – the pyramid stuff was higher up.
Jarmo Moilanen / Marko Riikonen
Monday, 24 September 2007
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.)
By Patrik Trncak
By Patrik Trncak
Sunday, 24 September 2006
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.
By Marko Riikonen
By Marko Riikonen
Saturday, 13 May 2006
Doubled Halos?
This image was taken in Fukushima pref. in Japan, by Mr. Tasan (handle), May 5, 2006. There are two halos -- the lower one seems a 22 degree halo, but what is the upper one? I think it can be a 24 (or 23?) degree halo, a circular Lowitz arc or a 23 degree plate arc. What are your opinions?
Subscribe to:
Posts (Atom)