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.

Subvisual odd radius halos in the UK

In the afternoon of 26 March, 2017, I was spending time outdoors with my family and wasn't too well equipped for serious observing. Of course, I had paid some attention to cirrostratus clouds drifting in the sky, but most of the time I struggled to see any significant halos. There were just occasional patches of 22° halo: or at least that's what I thought they were. But then the upper suncave Parry arc appeared so I had no choice but to start photographing immediately. After all, you don't get Parry every week, and in fact this was my first such encounter in 2017. During the next 20 minutes or so, I took a decent set of photos, but then gave up as it appeared that the display had become insignificant again.

My hope was to find a few more halos in the post-processing, and stacking did a good job indeed. The stack shown above is from the first 50 frames and covers a total of 196 seconds. On the left the unsharp mask is applied on individual frames before stacking. The version in the middle is a gradient-subtracted average stack, which is further processed by using the blue-minus-red subtraction technique on the right. In addition to the usual stuff and the Parry arc, we can identify upper and middle Lowitz arcs as well as a short piece of helic arc to the left from the circumzenith arc. But that's not all - there are also odd radius circular halos.

For comparison, the stack below is from the last set of 30 frames that I took more than 30 minutes after the last signs of the Parry arc had disappeared. This stack covers a total of 174 seconds. I didn't really expect to find anything special at this point, but took the photos anyway out of curiosity. Apparently the odd radius stuff is still in play. My feeling is that it had been there all the time, possibly long before I noticed the Parry for the first time and also long after I had got indoors to celebrate the Mother's day dinner.

What is shown below is an attempt to make the scene as clear as possible by combining photos from two different series into one stack. 100 frames are included, covering 13 minutes in time but missing about six minutes in the middle. My interpretation is that the relatively typical pattern of 9°, 18°, 24°, and 35° halos is complemented by the exotic 13° halo. But I'm not sure and it would be great to hear what readers might think of the case. Whether the 20° halo is missing altogether or masked behind the suspiciously wide 18° halo, I am not sure of that either.

Some spotlight stuff from a bridge

My previous post was about one photo from the night of 10/11 February 2017 in Rovaniemi. Here are the rest. Bridges are good places for spotlight stuff. You can get pretty much any elevation and have a view from zenith to nadir as shown above. I should have used this nadir-zenith configuration more, its benefits didn't really sink in until late season. It has a potential to give answers to questions on crystal orientations and shapes that higher up pointing view wouldn't give.

Name A Beer!

© The Halo Brewery

I recently contacted Callum Hay and Eric Portelance at the Halo Brewery based in Toronto, Canada, to see whether they would be willing to consider a few suggestions for a name for a halo themed beer. I was very pleasantly surprised when they replied that they would be open to any ideas as they sometimes found it difficult to find a suitable name for their beers. Callum and Eric brew in the Belgian and American traditions but employ a fair degree of experimentation and artistry,

"We use fruit, spices, and other unique ingredients in our recipes to complement the flavours of our malt, hops and yeast. The more interesting ingredient, the better."

Now here is where I would like to hand it over to you. I know that there are many beer connoisseurs amongst our readers and contributors who really appreciate a fine ale. This is a unique opportunity to have a beer named after the subject that is close to our hearts. Perhaps you would like to name it after one of the early pioneers such as Lowitz or Parry, or perhaps you would like to immortalise a particular rare and exotic halo. Likewise, maybe you could also suggest a particular style of beer like a Supralateral IPA, a Wegener dubbel, a Tricker trippel a Subsun Sour or a Parhelic Stout. Use your imagination and let's see what we can come up with. Any and all suggestions will be passed on to Callum and Eric for their consideration. I can't promise that they will definitely use any names we suggest but it will be a fun challenge all the same!

For more information about the Halo Brewery and the work they do, please check out their site,

http://halobrewery.com/

© The Halo Brewery

Halo Phenomena in Olaus Magnus’s Historia de Gentibus Septentrionalibus (Part 2)

Halo phenomena in Historia de Gentibus Septentrionalibus, Bk. 1, Ch, 14. Image from www.avrosys.nu

The Swedish Olaus Magnus’s 16^th century Historia de Gentibus Septentrionalibus (History of the Nordic Peoples) has several chapters and woodcuts dedicated to halos. The first part of our series introduced this medieval best-selling work, and concentrated on parhelia and paraselenae as described by Olaus. This time the halos of Book 1, Chapter 14 are to be introduced, which is the very first section of his work where he deals with halo phenomena. 

We don’t  know whether Olaus saw any halos in his life, though in Chapter 17, he notes that there were three suns and moons in the sky at the time of his birth. Besides classical natural historical authorities like Pliny the Elder, his information comes most probably from accounts collected during his journeys, which he later recorded according to his own understanding and imagination. He introduces halos as seasonal phenomena, which are connected to early spring and hardly last longer than two and a half hours. He does not even start the list of halo forms with the most frequent ones: the first halos that he describes are the parhelic circle and three patches on it which could be interpreted as the 120° parhelia and the anthelion.

“Up in the north when deep snow covers the earth round about the vernal equinox, circles sometimes appear with the following formation and position. The most spacious circle, spread over the horizon is entirely white, as also are three small circles, each hanging separately from its circumference; towards the east, however, these are distinguished by their yellow colour, as if they are trying to resemble the sun (…)”

Olaus then continues his presentation with the more frequent forms. The 22° halo, the parhelia and the upper tangent arc are easily recognizable, and so is the circumzenith arc. But what comes afterwards (a blackish rainbow and a dusky but colourful one) is more difficult to interpret. We could deduce from their position in the woodcut that he may be talking about supra- and infralateral arcs, but since the depiction and the description are not obvious and they contradict to what such arcs look like in reality, we should not draw further conclusions from them. Olaus’s description is typical of similar accounts: he presents events which took place over a longer stretch of time, disregarding the changes in halo forms as time passes, what is more, he probably never witnessed such halos in the sky.

“(…) and even the body of the sun can be surrounded by a corona or halo of rainbow hues, and has reddish likenesses of itself attached on either side. From these likenesses, or if you wish, from these two suns,  two semicircles, like bows, rise to intersect each other; eventually, after expanding as halos do, they vanish. Around the navel or centre of the most spacious of these circles can be seen an inverted rainbow, which gleams in a cloud of fine vapour. Next there appears another blackish rainbow, opposite to the first in colour and position. Afterwards this bow, dusky but ever varying in colour, as is customary with the celestial arc or rainbow, extends towards the south, crossing through the most spacious of the circles.” 

Vädersolstavlan by Jacob Heinrich Elbfas. Image from Wikipedia

The woodcut illustrating his chapter might look familiar to people interested in historical displays. It bears resemblance to Vädersolstavlan, an oil-on-panel painting by another Swedish man, Jacob Heinrich Elbfas. The painting is the 17^th century copy of the now lost original ordered by the Swedish reformer Olaus Petri, and created by Urban Målare. It shows the halos that appeared over Stockholm on 20 April 1535, 20 years before Olaus Magnus’s book was published. The country at this time was turning to the Lutheran faith, and religious reformation fuelled serious conflicts and controversies between the ruthless reformer king Gustav Vasa, and more moderate Protestants like Olaus Petri. Both parties saw a celestial sign in the appearance of this halo phenomenon, and we can easily deduce that the Catholic Church was also prone to interpreting the halo as a divine premonition. Olaus Magnus himself was the last Catholic archbishop of Uppsala, who had to live in exile for the rest of his life after Sweden had turned to the new religion. Although he does not mention the ominous 1535 Stockholm halo and its contemporary reception, but the striking similarity between the woodcut and Vädersolstavlan might indicate a conscious choice for deciding to start his description of halos in Historia de Gentibus Septentrionalibus with this very emblematic appearance.

Either influenced by his own fate, or due to contemporary superstitions, Olaus attributes bad omens to such halos. Much of his chapter elaborates on what misery they may bring. As he claims, they “always cause, either by their own nature or for some other, hidden reason, the worst consequences in the time immediately following them: for example, ominous thunderings and thunderbolts which throw houses and animals to the ground; capturing and killing of nobles and common folk, and pillaging of the people in that region, not to speak of enemy fleets, pirate raids, and acts of arson; and when the circles disappear at the end of spring, grains of suphur commonly rain down in a stinking mist.”

By Ágnes Kiricsi


English translation by Peter Fisher and Humphrey Higgens from: Olaus Magnus, A Description of the Northern Peoples, 1555, Vol. 1. Ed.: Peter Foote, Hakluyt Society, 1996.

A Rovaniemi display and simulation

This display shows the very common arcs that according to simulations seem to arise from 3b5 type raypaths in Lowitz oriented crystals (where b signifies basal face). I avoid using any names, first because I am uncomfortable with current nomenclature and second, because the situation with these kind of arcs has become confusing. I am getting to have a feeling that there may be two or even three different halos that look quite similar but have different formation.

The match between photo and full simulation on the left is poor. Neither the curvature nor intensity of the simulated 3b5 arcs match with those seen in the photo. The inner arc is curving less steeply in the photo as compared to simulation. And it is most intense near 22° halo while in simulation the arcs barely reach to touch it. I found not possible to make the arcs extend all the way to parhelia in simulation. The filtered simulation on the right shows the maximum extent of the arcs.

Concerning the shape mismatch, it is also noteworthy that the arcs in the photo are separate from 22° halo while the simulated arcs reach to touch it. Added to the right side filtered simulation is circular Lowitz arc to see if that together with the 3b5 arcs could explain what is seen in the photo. The shapes don't quite align. It seems to me there are no Lowitz arcs in this display.

The simulation light source elevation is -32.3 degrees. Concerning the crystal parameters, the parameter table below is not the version that was used to make the simulation on the right, I didn't happen to save the last permutation. But it is close enough. There is a plenty of leeway for 3b5 arcs parameters so exact numbers are not important.

One other thing worth noting in the photo is the subparhelic circle inside subparhelia. Simulations tell it can be formed by Lowitz oriented crystals as German observers demonstrated recently. Or it can be formed by highly triangular crystals. The effect was visible to the eye and its glitter gave an impression of broadness apparent in the photo.

The image is an average of fourteen successive 30s exposures, stacking done with Halostack. The night was 10/11 February. I was a bit late from the show because I was keeping an eye too long at the lowering of the cloud base from my apartment, suddenly realizing when the chimney of the distant power plant disappeared that I have to be going and quick. It was full fog when I curved to the scene on the ski slopes side of Ounasvaara and streetlamp parhelia were awesome solid beams. Obviously, my procrastination at the apartment asks for at least 15 minutes of unremitting self-criticism at the next halo meeting. Typically if it is like that when you arrive, then it is already late when you are ready to photograph. Sure enough, by the time I had it all set up, snow flakes were already falling among the diamond dust just as forecasted. But because the fog was still there the diamond dust was able to hold on to it for enough long to me to secure series of photos at several lamp elevations. Of course the rather ample snowfall (which was actually boosted by the diamond dust to even more) greatly reduced contrast, giving a milky background. Considering these far-from-optimal conditions, the display was surprisingly good.

The Earliest Known Photograph of a Halo

Following the publication of the recent Kertész post, a lively discussion ensued as to what is the earliest known photograph of a halo, either in black and white or colour? This brought to mind Marko's post on his blog submoon, about the first recorded halo from Lowitz orientation with a 315/325 raypath. In that post, he includes a photograph taken by Paul Schultz on a 1905-06 expedition to Alaska and later reproduced in the book Ten Thousand Miles with a Dog Sled by Archdeacon Stuck (Scribner's, 1914),

Very recently, I also had the great fortune to come across a book, Cloud Studies by Arthur W. Clayden, (John Murray, London, 1905) which includes two photographs of halos. The first shows a 22° halo which exhibits a thickening around the area of the upper tangent arc and a second one which shows a section of the parhelic circle. Considering the book may have been in preparation some time prior to publication, these images might even be slightly older.

Now the question I would like to pose is can these really be the earliest photographs of halos ever taken? I have an extremely hard time believing this to be the case. My gut feeling is that earlier examples must be in existence somewhere. Photography had been around for nearly eighty years when these photographs were taken. The first black and white image was produced  in 1826-7 and the first colour image in 1861. The quality of photographic equipment and technique had been refined to such an extent by this time that high quality images were able to be produced by the average photographer. However, in the hands of a skilled practitioner, large format plates coated with slow emulsions were capable of recording some of the finest images that have ever been produced, exhibiting the most exquisite detail and tonality. In the following examples of early photographs, we see that the clouds and the sky play a principal or prominent part in their composition,

Sky Study, Paris, Charles Marville, 1856-7. © Metropolitan Museum of Art.

September Clouds, Roger Fenton, 1859.

Seascape at Night, Henry Peach Robinson, 1870.

So here is where I hand the investigation over to you to play detective. The bar has been temporarily set at 1905, but I am quietly confident that with a little effort we can push the timeline back into the nineteenth century and even further, possibly back towards the 1850's and 1860's. One last sobering thought to bear in mind. The very first photograph ever to be taken was View from the Window at Le Gras by Joseph Nicéphore Niépce in 1826-7 and was taken from a vantage point looking out on to the open sky which could potentially have contained a halo.

View from the Window at Le Gras, Joseph Nicéphore Niépce, 1826-7.

Happy hunting!