More diamond dust in Rovaniemi

Last night diamond dust formed again in Rovaniemi with help of Ounasvaara ski resort snow guns. Two photos of what was seen in the light beam of a bright lamp are shown here.

In the upper image are diffuse anthelic arcs. In the lower image a number of common halos are seen together with Moilanen arc. Three white strikes extend from lamp to different directions to the left. Possibly these are parhelic circle (and parhelia), helic arc and superparhelia. Or, some of them may be artefacts formed by the lamp reflector.

Temperature was -6°C and it was overcast sky. The display was limited to the vicinity of the snow guns, these photos were taken at the top of the skiing flank. I was not able to get very far from the lamp, which accounts at least partly for the numerous separate crystals and diffuse looks of the halos. The lamp was on the elevated ground, but I did not make an estimate of the lamp angular elevation.

These are just two randomly chosen photos and may not represent the best output. Much more photos were taken, including crystal photos. I will return to these at some later time.

Halo Complex 15th October 2007

After over 90 days of above 90 degree temps and no halos this half-way decent display shows itsself in high clouds. Upon leaving work, I got quite a few photos. In all I got 22d halo, parhelia, upper tangent arc, bits of parhelic circle, infralateral arcs, 120d parhelia, and an upper suncave parry arc. While on the road I observed a rather bright 120d parhelion on the left side. As the patch of cloud shifted to the north the blue spot appeared and got several photos of it. When enhanced, the bluespot shows green, blue and purple and possible red but can't be sure. The one photo showing the Parry has ugly power lines but could not help that because I was shooting out the car window. If you wondering if I was driving at the time I wasn't because one should not drive and take photos at the same time. During those halo free days the temps were breaking records even in October and it was nice to see halos again.

Blue spot gets more colours

Blue spot is the colour feature of the parhelic circle occurring at the anthelic region of the sky. In addition to the blue, the theory predicts also green, but no red. Yet in several observations also red colour has been reported. However, because the red has never reproduced in photos, the observations have been doubted.

The image here shows two versions of a simulation of plate crystal parhelic circle in the anthelic region of the sky. The upper one has not been processed, the lower one has an overall levels adjustment to enhance colours. It looks like there is red present in addition to blue and green.

So it may be that observations of red may have not been wrong after all and that the theory (and naming) of the blue spot needs to be reconsidered. Lacking of the red in photos may be explained by film and sensor sensitivity issues. Even though the colors are seen with naked eye, they are still weak and some wavelenghts may be more prone than others to be not captured by the photographing equipment.

The simulation was made with a software developed by Jukka Ruoskanen. Sun elevation for the simulation is 25°, the plates have aspect ratio of 0.9 and tilt 3°.

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.

Anthelic arcs in Finland

On August 28th anthelic arcs appeared in the northern part of Finland. My coffee break was suddenly halted as watching from the window I noticed several arcs. Once outside my eye was first caught by well developed parhelic circle. Then, looking up I noticed a colourful Wegener arc. Colours were red on the bottom and blue on the upper part. In the later stage of the display I noticed faint X at the anthelion indicative of the diffuse/Tricker arcs. I had no camera but my friend borrowed his camera equipped cellphone. Image quality is quite poor, but halos are still recognizable. Also Parry arc and 120 parhelia were present. Other halos were 22halo, parhelia, 22 upper tangent arc, parhelic circle, circumzenith arc, infralateral arc and supralateral arc. The display was noticed over large areas in Finland. More photos is here. Also see the photos by Arto Oksanen and Panu Lahtinen

Bright 120° parhelion over The Hague

Sunday, September 2nd 2007, The Hague, The Netherlands

After a cloudy morning, the low clouds broke up and both the sun and higher cirrus clouds became visible.

The appearance of the cirrus was an indication for me, to keep a keen eye on the sky. That policy was worth-while, because a short time later, at about 11.35 C.E.S.T., a part of the Parhelic circle appeared, together with a remarkably bright 120 deg. Parhelion, in NNE-ly direction. Both the parhelic circle and the Parhelion presented a clear brownish-reddish fringe colouring. Immediately, I fetched my mobile-phone-with-camera, and made the picture, accompanying this message.

Frank Nieuwenhuys

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.

Wegener arc on webcam

On Mar/3/2007 I captured a halo display with a remote webcam in Oklahoma/USA. The camera image shows a bright parhelic circle, 120° parhelion and a rare Wegener arc forming a cross on the parhelic circle. A time lapse movie is available here: 

http://www.parhelia.de/storm/2007/flash/wegener.html (Flash)

Mid-elevation halo display with column crystals in control

Throughout my work day there were a number of halos that were coming and going. Around midday there was 22d halo, circumscribed halo, parhelic circle, and parhelia. Later on at break time I got 22 and circumscribed halos and there was a nice infralateral arc on the left and a possible lower suncave parry arc not sure on that need help to identify short piece of arc to the left of 22d halo. Before I left work I imaged an upper suncave parry arc. The final stage had nice upper tangent arc and a complete supralateral arc.

Odd radius halos in diamond dust in Finland

On 23 February an another diamond dust display with odd radius halos occured in Vaala, Finland. Temperature was dropping from -29°C to -24° during my observation.

A parhelic circle and circumzenithal arc were present with nice parhelia. A subsun and subparhelia were also seen as sparkling ice crystals in front of the ground.

Odd radius halos labelled in this enhanced photo are A) a pyramidal heliac arc, B1) upper 24° plate arc, B2) lower 24° plate arc and C) upper 23° plate arc.

The most brightest odd radius halo was 18° halo and in some photos there probably are also 9° upper plate arc and 20° halo. The ice crystal cloud was produced by a local heating plant about 2 km away. More photos can be found here.

Reflected Lowitz arcs in Finland

On 30th January 2007 I found that local district heating plant was causing a nice diamond dust display. Temperature was -22 C and the steam crystallized immediately. Only a few hundreds meters from the plant was already a plenty of crystals, but the best was about 2 km from the plant.

There I drove to a small road and got out and saw a display like never before. Parhelia were very bright, like fireballs. Also circumzenith arc was bright, but 22 halo was quite weak. Almost full parhelic circle was present with faint 120 parhelia, that looked more like pillars than fuzzy balls.

I had a film camera and eventually run out of film. The only choice was to drive home to get digital camera and fisheye lenses. On returning back the display had lost intensity and the 120 parhelia were completely gone. Anyway, I took about 80 photos with digital and later stacking of those photos revealed faint reflected Lowitz arcs rising up from the parhelia (marked in the photos with arrows). More photos of display is here. The looks of the display is quite similar to the one that was observed by Jari Luomanen a year ago. See photo here.

Combination of high level cloud and diamond dust activity

On the evening of 30th January cirrostratus clouds filled the sky and odd radius halos (9, 20 and 35) were seen in the Moonlight in Hyvinkää, Finland. The 20 and 35 halos were very weak, and couldn't be seen with naked eye. In addition to the high clouds there were good but fast moving diamond dust areas on the ground level. At times the halo display was a combination of cirrostratus and diamond dust halos. In the photo on the left the parhelic circle was caused solely by diamond dust, whereas the other halos were mainly originated in high clouds. A collection of photographs taken by Jukka Ruoskanen is here. 9 degree halo was also seen in Espoo by Timo Kuhmonen, in Helsinki by Marko Riikonen, in Turku by Ismo Luukkonen and in Tampere by Jari Luomanen.

Exciting divergent light halos were photographed as well in Hyvinkää. A more detailed description of the divergent light halos is here.

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) .

High sun halo display in Bolivia

Louise Emmons sent these two photos of a halo display seen on 9 October, in Noel Kempff national Park North-Eastern Bolivia. The halos are a bright circumscribed halo, a probable 46° infralateral arc and parhelic circle.

"It was one of the most amazing phenomena that I have seen in my life, together with a total solar eclipse with ground waves and an immense fireball", writes Emmons.

The display lasted at least for half an hour. In about 6-8 h it was followed by a strong rain front.