Sharp Lowitz & Parry display, in short time [2023-04-04]

Here are some nice ice halos at the passage of a particular layer of clouds, during a clear sky day (2023-04-04, from near Dole, Jura, France). This clouds layers gave an extraodinary sharp looking display of ice halos, as I rarely saw in 15 years of watching. I was then in the good spot at the right time, for this one. While I was taking care of my lawn, during a clear sky day, I saw some high altitude clouds coming from the north, and decided to take the bet I will have some ice halos, but I did not epected that kind of sharp halos. In all the below images, clouds are coming from the left (North-East).

On this first stack image, you can see the Wegener arc, with almost the part crossing the parhelic circle. There is also the 120° parhelion with reddish edge as well as on the circle.
Process is (as an example of how I do usually, for the image shown above,
named 2023-04-04-[14h57to15h37]-bw-[4-2]-UsM(11)-5s5-notrack-UsM.bmp):
→ B-R ( -bw ) rendering of all the images of the sequence ( -[14h57to15h37] ),
→ 11th stack ( (11) ) of the sequence with 4 images ( -[4 ),
→ then Unsharp mask on this stack ( -UsM ),
→ then a new stack (with Registax, without the track on the sun ( -notrack ))
→ of 5 ( -5s5 ) of last stacks (those ones taken every 2 images ( -2] ))
→ then one more Unsharp filter ( -UsM ) to end it.

Later, like 5-6 minutes later, the layer of clouds enter the 46° FoV from the sun, which gave the most impressive part of the display to me.

Here is one single image, with just B-R rendering (no UsM or what so ever).

Then 2 stack versions witht this image along with some before and after, to see more clearly the Lowitz & Parry display, (on the above one, we can see parts of 46° halo, but not in whiole, because of the hole in the clouds crossing the view... I guess)

and with the images when the clouds are on the side of the sun from my point of view. I even manage to watch clearly the circumscribed halo while i was cutting my lawn.
You can also see the left part of lower Parry arc tangent with the circumscribed halo.

A last part of the display, with clouds on the bottom left of the sun, to see the extension of the lower Lowitz and the extension of the left part of the Lower Parry, tangent to the circumscribed halo.
For this stack, a "min" function is applied during the stacking process, in order to keep the minimum value of each pixel while stacking, and try to make the black forms therefore the colored halos more visible.

A crop on the left sundog, to see the Lowitz crossing and the 2 Parry arcs.

I have not presented any colored versions, because of the heterogeneous form of the clouds mask the halos for this display.

Finally, a time-lapse of the display is available here, which a compilation of differents time-lapses (one for each processing type). From those images are extracted the previous posted here :
www.flickr.com/photos/gaukouphoto/52808574767/in/dateposted/

All images are taken with Canon EoS 6D + 8mm Samyang lens from my roof windows, South-South-East side.
Settings: 1/1000s, ISO100, f/9,4, 1 image every 12s.
Sun mean height is 47° at the time of the sequence.

Google Drive folder shared, with all the images presented here, and the time-lapse.
I still have all the raws of the sequence if needed too.

Display of 3rd August 2017 in Pskov oblast, Russia

Every frame of animation is stack which covers 2,5 min. Colored version is here

At the begining of the display, beautiful cirrus covered the sky, but I did not notice any halos at the time. When I came out a little later, I was surprised to see a bright parhelion and a middle Lowitz arc which crosses it! Cumulus limited the display, so I could observe halos only in gaps between these clouds. There was one short episode when I saw bright upper tangent and suncave Parry arcs. The following rare halos were found in the stacks:

 -well defined upper and middle Lowitz arcs (1) and possible lower Lowitz arc (2)
-part of helic arc (3)
-supralateral Tape arc (4)

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.

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.

Weak odd radius display with possible column arcs

This display occurred on 22th February 2017 in Izborsk (Pskov region, Russia). In the morning it was sunny and the first cirrus started to arrive around 13-00. In that moment, I saw a faint 22° halo, but it was visible because the cloud layer was smooth. Also it seemed to me that I saw a 9° halo through the viewfinder of my camera. The stacks showed pyramidal halos such as 9°, 24° and 35° halo.

The 24° halo looks pretty curious, because B-R processing shows the pause in 24° ring in area of upper tangent arc. It reminds me of 24° column arcs from crystals with big tilts. 9° halo also looks curious, brighter on the sides than on the top, what looks like 9° column arcs.

What do you think of that? 

Lowitz - the new normal?

In 2017, halo activity in my part of the United Kingdom has so far been very quiet with not much to get excited about apart from the occasional odd radius lunar halo. However, on the 6th February things improved a little with a nice little display which included 22°, both parhelia (sporting parhelic tails), uta, possible Parry, cza, supralateral and all three Lowitz variants. The upper and lower Lowitz were vestigial, but the middle Lowitz illustrated here was quite clearly defined.

This burst of activity got me ruminating about the frequency of certain types of halos and the nature of “rarity”. Compared to many of you 'old hands', I am a comparative newcomer to halo observation. When I first started to observe, many halos were still considered to be extreme rarities or at least exceptionally infrequent. Others, such as the Kern, were so rare that they were considered to be the Holy Grail of halos, so few were their sightings. What I have noticed over the last few years is that many of these rarities are seemingly becoming far more frequent and in my own mind at least, I have downgraded them from ‘rare’ to ‘infrequent’.

Take the Lowitz arc for example. It is only a few short years ago that its very existence was being doubted, controversial to say the least. First, there were a few sightings, then a trickle of photographic images emerged which confirmed it as a reality. Over the past ten years, their frequency has seemingly increased to the point where I will see several per year and look out for them as a matter of course. Whilst not commonplace, they are certainly hovering somewhere in that vague, nebulous no-man’s land between infrequent and relatively frequent. Likewise, the Kern. At first a mythical creature, but now we are seeing the first drips which will eventually become a trickle….

So what has caused this apparent change in frequency, this downgrading of status? I would like to posit two possible causes: the ubiquity of digital imaging and advances in image processing. It is not that these halos are actually becoming more frequent in reality but that the effect of digital imaging and the development of image processing techniques are revealing them to be present in many more displays than were hitherto thought. In the past, one would take a roll of traditional film, but prior to image processing what did one do with them? Answer, nothing in most cases. You either saw the halo on a particular frame or you didn’t. This resulted in some of these rare halos only showing themselves under exceptional conditions. With the advent of inexpensive digital cameras and image processing software we saw far more phenomena being recorded. However, it is only with the introduction of the B-R processing technique pioneered by Nicolas Rossetto and perfected by Nicolas Lefaudeux and to a lesser extent image stacking, do we really notice an apparent increase in all types of rare halos. These techniques alone have been responsible for the massive increase of rare halo frequency and the identification of several new halo species. We have now reached a point where what was new and exciting yesterday, is passé today.

I think this trend is going to continue as more and more observers embrace these new methods of working. We have already seen it occur in the wider field of atmospheric optics where photographic identification of higher order rainbows, especially the third and fourth orders, are now becoming a reality. One might argue where is the hard evidence to prove this is anything but a theory or personal opinion? This evidence is indeed hard to come by, however projects such as Lefaudeux's 'HaloCam' has demonstrated without a shadow of a doubt that certain halos are far more frequent than previously thought. For example, he has very clearly demonstrated that the 46° halo is present almost as often as the 22°, whereas at one time it was considered to be a very infrequent visitor to the skies. So not only will this trend continue, I think it will also accelerate, especially in the field of spotlight displays where new halos are being discovered on a very regular basis. Even in daylight displays, new halos are still being captured from time to time using these techniques.

A few years ago, it seemed like everything that could be seen had been seen. We are now on the cusp of a new era of halo research. Today may indeed be considered passé by some, but tomorrow is definitely going to be tremendously exciting! I want to be a part of that new wave of discovery.

Alec Jones

Subparhelia and sub 120° parhelion on ice surface

average stack of 15 frames

In the morning after new year's night, I noticed through a window cirrus clouds, and I went to observe. While I was waiting for the appearance of halos, I noticed weak subparhelia on the ice surface. Out of curiosity, I decided to look for a place where they could be brighter, and I found it (1, 2). It was quite a small area near a coast, almost all sides limited. There I saw not only bright subparhelia, but also clearly visible sub 120° parhelion in pillar form.

maximum stack of 3 frames

It was perfectly visible even when I did not move. The temperature was negative only at night until this morning. In the previous day it was positive (around +4 degrees of Celsius), as during of the observation (0...+1). 

At that time, while I was shooting halos on the ice surface, in the sky appeared parhelion and 22 degree halo (3). Later the upper tangent arc was spotted in cirrus clouds (on the stack also well visible supralateral arc - 4). At the end of the day, I also noticed weak and wide circumzenithal arc (5) from low sun.

Date: 2017-01-01

Diamond dust halos in spotlight beam in the evening of December 2, 2015

By Marko Riikonen and Olli Sälevä

Here are shown the rest of the photos from the night that yielded the second capture of the anomalous Wegener/Hastings. From the golf course parking lot, where we took those photos, we walked into the golf course, and were able to place the lamp even lower down.

The display was no more as good, but in the photo above and two below there is nevertheless again visible a short patch of Wegener/Hastings on top of the 22° halo. Whether this one has an anomalous curvature, is hard to say. Judging from the 46° stuff that is seen against the forest, the crystal orientation would rather be column than Parry, because it has the looks of a 46° infralateral arc, not Tape arc, which would be more spotlike.

The swarm shifted and we followed it to a field over the river. There we continued taking photos, as shown below, but that was cut short when the spotlight started flashing at 10 pm. The 60Ah car battery had run out of power and it was game over for the night.

It was painful because the conditions seemed to continue at least for the next five hours and probably even amping up as the temperature rose from -11 to -5 °C. Under clear skies such a warming would have killed the diamond dust, but now it was overcast and the clouds kept hanging low, meaning they were likely nucleated to ice by the snow guns.

From this on the winter’s halo hunt continued with two batteries, but on one cold night in January even that was not enough. That time, however, a helping hand was extended by the Ounasvaara ski center folks, who borrowed one of their batteries.

Pyramid crystals and odd radius halos, part II

More halo and crystal photos from the 20/21 January night. While this second crystal sampling and photographing session was under way, the display in the beam was photographed constantly, but again odd radius halos are not visible in the photos, expect perhaps for a suggestion of 35° halo at one stage (not shown). Yet again the sample was littered with classical pyramids as shown by the images in the gallery.

The picture above is an appearance of odd radius halos after the crystal business was over with. It is a “blue minus red” (br) of stack with total of 9m30s exposure and contains 9°, 18° and 35° halos. Three more halo images are in the gallery, first a single frame from the stack above, then two that are versions of another stack, the br displaying full 46° halo.

Jarmo Moilanen / Marko Riikonen

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.

By Ágnes Kiricsi

46° halo in Czech Republic

The April 21st 2007 was undoubtely one of the best halo days in this year. Observers from all over the Czech Republic enjoyed very bright 22° halo with tangent arcs and infralateral arcs.

We probably observed Wegener arcs and 120° parhelia, but this cannot be proven, because even fotos from Registax didn’t help us to clearly identify them. Anyway, Martin Popek saw that day very nice 46° halo and he took these pictures which were stacked from 40 images in Registax.

As the Sun was setting down, more halos appeared. In the second picture you can see parhelion with a part of parhelic circle (parhelic tail), 22° halo, circumzenithal arc and probably supralateral arc.

Edit: It isn’t supralateral arc in the second photo, but 46° halo because there is no upper tangent arc. That signifies absence of horizontal oriented columns, which are necessary in order to make supralateral arc.

46° halo in Czech Republic

The April 21st 2007 was undoubtely one of the best halo days in this year. Observers from all over the Czech Republic enjoyed very bright 22° halo with tangent arcs and infralateral arcs.

We probably observed Wegener arcs and 120° parhelia, but this cannot be proven, because even fotos from Registax didn’t help us to clearly identify them. Anyway, Martin Popek saw that day very nice 46° halo and he took these pictures which were stacked from 40 images in Registax.

As the Sun was setting down, more halos appeared. In the second picture you can see parhelion with a part of parhelic circle (parhelic tail), 22° halo, circumzenithal arc and probably supralateral arc.

Edit: It isn’t supralateral arc in the second photo, but 46° halo because there is no upper tangent arc. That signifies absence of horizontal oriented columns, which are necessary in order to make supralateral arc.

Moon halo over Southern Finland - oriented columns in command

Little after midnight on the night of 5-6th January a fairly bright 22 halo and upper tangent arc appeared in high clouds. At this stage nothing implied that anything better would be on the way. However, at around 1.30 a.m. the halos arising from oriented columns had got much better and upper and lower tangent arcs stretched out to form a circumscribed halo. Infralateral arcs and a 9 halo appeared as well. Judging from the quality of circumscribed halo and infralateral arcs at the maximum phase one might suspect that rays scattered by oriented columns may have partially contributed to the intensity of the 9 halo.

The display ended at around 4 a.m. when low level clouds rolled in. Shortly before that 46 halo and parhelic circle were well formed (although faint). According to the reports so far the display was best seen in Tampere (photos by Jari Luomanen) and in Riihimaki (photos by Jukka Ruoskanen) .

Wegener Arc - Stockholm

Göte Flodqvist recorded this display at Stockholm on January 3rd. Wegener and subhelic arcs were evident with a bright supralateral arc and a 46° halo. The HaloSim. simulation parameter file can be downloaded here.

Parhelion legs in Italy

9.1.2006 in Colfosco (Italy), HOP member Lukas Kosarek seen some halos on diamond dust. He observed 22 deg halo, 46 deg halo, supralateral arc, circumzenith arc, subsun, subparhelia, 22 parhelia and faint upper tangent arc. About 10:00 UT he seen and take photo of Parhelion legs - interesting phenomena of ice halos. He say: " I seen two orange arcs, join parhelion with subparhelion. It was bright on right side of halo display". Some photos of this display are here: http://www.fotoagrafika.wz.cz