Saturday, November 17, 2007

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.

Thursday, November 15, 2007

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.

Thursday, November 08, 2007

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.

Wednesday, November 07, 2007

Pyramidal crystal halos

A funny coincidence that a halo-observer may want to experience is travelling to Egypt and seeing some pyramidal crystal halos.
This odd-radius display was photographed by Márk Laczkó of Budapest, Hungary somewhere over the southern borders of Romania. He was sitting on an airplane heading towards Egypt on 27th October. When he realised they were flying in cirrus clouds, he deliberately started looking for some halo phenomena. The surprisingly well distinguishable 18°, 20°, 23° and 24° halos were visible for about a minute at 06:21 UTC. Unfortunetally there is no documentation or report of a possible 35° halo. The original photo and two other pictures are also available (#1 and #2).