More photos from three weeks ago in Rovaniemi

It seems putting the photos of the recent displays to my web page will delay. So, in a meanwhile here are two more photos of the display three weeks back.

When light source is at 0° elevation, some difficulties arises in identifying certain halos. Tricker arc and subanthelic arc merge together, as do helic and subhelic arcs. However, the subanthelic arc is formed by Parry-oriented crystals, while Tricker arc is from singly oriented columns. Because in this display the 46° supralateral arc is rather strong, and there are only weak indications of 46° Parry or Tape arcs, probably singly oriented columns were in command. The even brightness of the Tricker/subanthelic loop is also typical for Tricker arc. Subanthelic arc has strong brightenings on the sides - at least in the simulations - and that is actually what seems to be present in the the display of last weekend.

The reason why halos are seen so strongly in the halogen light is probably the relatively dark background sky as compared to sun or moon situation. Yet all the halogen lamp displays that I have photographed so far have been hampered by city lights. Once the crystal cloud drifts to the dark outskirts of the city, more intense appearances should be expected.

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

Diamond dust from Himos snow guns

Mika Aho was also on the halo move on Saturday 4. November. He headed for the Himos ski centre, where some 30 snow guns were operational. The trip was worthwhile. From skiing flanks spread an ice crystal cloud that, even though a bit unclean in appearance, presented some of the rarest halos.

These rare halos are best shown in the photo on the left where several white arcs are seen crossing the sky. Wegener, helic, subhelic, subanthelic and Tricker arcs are all present. Outside Antarctica subanthelic arc has been observed reliably only twice before, both times in Finland. Now Aho's photos add the third observation.

More of the display is to be found here. Like Oksanen, also Aho got halos in moonlight the following night. These photos are under the same link.