More results from the latest display in Rovaniemi

Here is some more material from the diamond dust in Rovaniemi three nights ago. After the heaviest Parry-crystal bombarding was over, Moilanen arc appeared, as shown in the photo on the left. Moon is giving the beauty spot.

I have crystal photos from this stage, but as usual, they give no glue to Moilanen arc. In the earlier Parry-stage there was no indication of Moilanen arc whatsoever, but I did not manage to get the crystals. This bugs, because comparing the samples might have pushed us forward in solving the mystery.

The upper left image shows parhelia from the streetlamp - the stripes that are parallel to the electric lines. Then there are also arcs extending slightly obliquely downwards. While visually parhelia curved towards me, these other arcs curved away and around me. As far as I understand from looking at divergent light simulations by Lars Gislen et. al, this effect is a 120° parhelion. In the photo only the brightest part of 120° parhelia is seen, visually the crystal glitter extented much longer. Also a full parhelic circle was seen visually.

The lower left photo shows is what was seen around the half moon at its best. For long time there was hardly no moon halo, although in the beam of the halogen torch a great display was present. Some indication of Lowitz arcs is present in the moon photo. The crystal sample may be representative of this stage, but I am not sure. Crystal photos of Lowitz displays are also very welcome.

Moilanen arc in Rovaniemi

Yesterday it was halos from sunrise to sunset in Rovaniemi. I was biking in the outskirts of the town in hope of getting into the heat of the things, but as afterwards many people told about good halos in and near the center, I think I missed the best action.

Anyway, here is a photo showing Moilanen arc towards the end of the display. The image is stacked from 14 frames taken during one minute. The ice cloud was elevated, only sparse crystals were glittering on the ground. Halos were generated by the snow guns of Ounasvaara ski center. Machines will be running continuously for the next three weeks as soon as it is at least -5°C, so more displays may appear.

Next night pillars were present, but the crystals were not that good.

Text: Marko Riikonen

Moilanen arc in Rovaniemi

Yesterday it was halos from sunrise to sunset in Rovaniemi. I was biking in the outskirts of the town in hope of getting into the heat of the things, but as afterwards many people told about good halos in and near the centre, I think I missed the best action.

Anyway, here is a photo showing Moilanen arc towards the end of the display. The image is stacked from 14 frames taken during one minute. The ice cloud was elevated, only sparse crystals were glittering on the ground. Halos were generated by the snow guns of Ounasvaara ski center. Machines will be running continuously for the next three weeks as soon as it is at least -5°C, so more displays may appear.

Next night pillars were present, but the crystals were not that good.

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.

Text: Marko Riikonen

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.

First diamond dust in Finland

The winter in Lappland was two weeks late but when it finally arrived last weekend, along came the diamond dust. Decent displays were seen here in Rovaniemi on two nights and one day. In the night time I used a bright lamp to create the halos. The photo here is from the second night showing the anthelic region with diffuse arcs. More photos, including all sky views, will follow some time later when I am done with them.

Text: Marko Riikonen

First diamond dust in Finland

The winter in Lapland was two weeks late but when it finally arrived last weekend, along came the diamond dust. Decent displays were seen here in Rovaniemi on two nights and one day. In the night time I used a bright lamp to create the halos. The photo here is from the second night showing the anthelic region with diffuse arcs. More photos, including all sky views, will follow some time later when I am done with them.