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 odd radii. Show all posts
Showing posts with label odd radii. Show all posts
Thursday, 18 May 2023
Thursday, 31 May 2018
Odd radii halos outbreak in the Czech Republic
There was an odd radii halos outbreak in the Czech Republic and Hungary in the past few days.
Multiple rare halo forms were captured.
Let me show you some of the photos:
These were taken by Jiří Kaňovský from Černotín, Czech Republic:
He managed to capture 9° contact arcs, 9° parhelion and 24° parhelion among others. Uppercave Parry was captured, too.
These were taken by me:
I am very confused about the halo forms captured here. First I thought I captured 18° parhelions, but now it turns out those are probabaly 20° and also 35° column arcs. There is also a faint lower 23° parhelion. 9° contact arcs are possibly captured, too.
The sun was 62° high at the point of the photoshoot.
I managed to stack multiple photos and edit those in Photoshop to bring out the halo forms.
Can anyone confirm that those are indeed column arcs?
Here are some .NEFs (Nikon's RAWs) if you're interested:
https://1drv.ms/u/s!ArJV0E31n7WMg0jl3Lh02eZjZy0p
Wednesday, 19 April 2017
Odd radius plate arcs in diamond dust display
The lamp in the photo is a couple of degrees below the horizon and there are 18, 20, 24 and 35° plate arcs. Plus a bit of a helic arc that in this kind of display could be of the odd radius type or at least contributed by it. This stage lasted only a few minutes after which lesser halos were visible for the rest of night. Under the outdoor light shining in the photo an upper 23° continued its presence longer. The display appeared on the night of 5/6 January 2017. Temperature was -27° C.
The photo below shows the location. The camera-lamp configuration is not the same as for the photo above, where the lamp and the camera were more level.
Wednesday, 5 April 2017
Some diamond dust odd radii in Rovaniemi
These photos were taken on the night of 9/10 February. In the image above we see odd radius stuff in the beam: circular halos and some bulges on them indicative of poorly plate oriented pyramids. The arc straight above the lamp on the broad 22° halo should be Parry / upper tangent arc rather than upper 20° plate arc. Visually I could not see the odd radii stuff but the appearance of the glitter made me think for its possibility.
One additional reason to suspect odd radii was the lunar display, which did not seem like your basic 22° halo stuff. The shot below was taken soon after I turned off the spotlight and it indeed has some not so clear odd radii, partly because of the artefacts. I photographed lunar also before the spotlight, and then the stuff was even poorer (this photo is not shown). So the spotlight in between gave the best display, which is of course what one expects
The enhanced version of this photo really brings out the artefacts. Br fouled it so completely that I am not showing it. Up until now I had had this nuisance entering the scene only in raw sun shine, but now it is has expanded its range to moon lit nights.
On the brighter side the artefacts became less disturbing when the milky background started clearing as shown by the photo below. Yet even then the br gives a rather ugly result.
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