Complex Halo Display, Borlänge, Sweden

On the 14th December 2018 at 12.30 UTC, Magnus Edbäck photographed an amazingly complex display in his home village of Utendal near Borlänge, Sweden comprising many extremely rare halos with at least one completely new halo form, a multiple scattering halo. Highlights include 46° contact arc, Hastings arc, extremely long Schulthess arcs and the rarely seen in daylight Ounasvaara arc. Like Marko Riikonen's 6th March 2017 Rovaniemi display, this one will go down in the annals of halo history and no doubt will be discussed and analysed for a long time to come. The two faint patches of light on either side of the 22° tangent arc are the new multiple scattering halo which at the time of writing has not been given a name. It is quite possible that the display was caused by snow guns in operation at the Romme Alpin ski centre situated about 12km away from Utendal.

Magnus has very kindly agreed to give an account of how he photographed the display.

"This is the story about my halo picture.

I was having lunch at my parents home when my mother asked me to look out to see how nice the sun was shining. At once I saw that this was not like any halo I had ever seen before. The sight of the sky was amazing. I then went to my home and grabbed the camera. My parents and I live next door to one another in Utendal, a small village outside Borlänge. I quickly checked that I had the appropriate lens, it was Samyang 14mm F2.8 that was on. The camera I used is a Canon 6D which I have modified with a Baader filter, mainly for use when I shoot the starry sky. From what I understand, the filter has no significance when shooting halo.

I went to a place on my parents courtyard where I could see as much of the display as possible. I quickly checked the settings on the camera, adjusted it to ISO200 and set the aperture to F8 to get a good depth of field. The day was quite cold (about 7 degrees below zero) and I was not wearing a jacket so I only took a few quick pictures (4pcs).

I then went back home to look at the pictures. On my way home, I also saw arcs to the north and I'm very sad that I did not take any photos of them. I quickly examined the images in Adobe Lightroom and picked an image that I uploaded to the Swedish astroforum www.astronet.se. I then went back to my parents to finish lunch.

Quite soon afterwards, I received comments on www.astronet.se by both Hans Bengtsson and Timo Karhula, who thought the display appeared to be something out of the ordinary. Hans thought I should send the image to Les Cowley and Timo thought I should publish it on www.taivaanvahti.fi. I received answers fairly quickly from both Les and www.taivaanvahti.fi. At 15:35 UTC 2018-12-14 I received mail from Marko Pekkola where he wrote:
"Congratulations Magnus of finding a new halo form in the sky in solar display! Several experts analysed this photo and Marko Riikonen identified one of the forms as the first multiple scattering halo of its kind.”  - Magnus Edbäck

Image processed by Nicolas Lefaudeux.

Image processed by Nicolas Lefaudeux.

Nicolas Lefaudeux has analysed and stacked the four raw files with background subtraction and produced these breathtakingly complex and beautiful processed images. The new halo is a multiple scattering [MS] halo, ie a "halo of a halo". These are extremely rare and can only appear in the brightest displays with very bright halos to forms.

This new halo is the uta of parhelion / parhelion of uta and it is the 5th MS halo form (after par of par, uta of uta, uta of pc/pc of uta, and cza of pillar). It requires both a very bright parhelion and a very bright uta to form. 

This uta of par/par of uta was the most likely MS halo form expected to be caught, because of its relative ease to appear in simulation and because it is not overlapped with other bright regular halos.

All images copyright Magnus Edbäck