Lunar Tricker arc and lower sunvex Parry arc in Finland

Tricker arc is not very common in lunar displays. That is not a big news, since it is often faint also in daytime displays. In Rovaniemi, a town at the Artic circle, Olli Sälevä observed this diamond dust halo display in 11 Feb 2006.

Other rare halo in the display is a lower sunvex Parry arc which was found later in one slide. Lower sunvex Parry arc is even rarer than Tricker arc. Unfortunately it is only faintly visible below lower tangent arc near horizon. In the lower picture picture red arrows points the red inner edge of lower sunvex Parry arc. Picture is enhanced to show the faint arc better.

Other halos in this lunar display were a Parry arc and a faint infralateral arc and a parhelic circle. Also street lights has halos around them like Y-shaped upper tangent arcs and parhelic circle look-alike parhelia. Olli photographed the display with film camera. He was not sure, but he thought that there was something going on opposite to the moon. So he took a photographs toward anthelion region as well. It was a nice surprice to him to find a Tricker arc in photos. Since moon elevation was close to 30°, Tricker arc is visible here only downward from the parhelic circle. Photo shown here is enhanced to look more like the original slide.

More photos taken by Olli Sälevä can be found here (rescanned versions will be upload later).

Odd radius halos and diffuse arcs in Fairbanks

Alaskan town Fairbanks is renowned for it's odd radius halos during the winter. On 10. March 2006 there was odd radius halos but also diffuse anthelic arcs - a treat much less commonly seen in Fairbanks. According to Walt Tape the display lasted for several hours and was different in different parts of town. Outside the town no halos were visible, which indicates anthropogenic origin of the display.

In addition to diffuse arcs, another curiosity was also seen: odd radius column arcs. While they are regularly observed in high clouds, in diamond dust they have occurred only once before, at South Pole. The photo above, taken by Tape, shows poorly developed 9° odd radius column arcs as enhancements on the sides of the 9° halo.

Elliptical halo in Helsinki

Elliptical halo appeared in the skies today on 26. March 2006. This was one of those rare long lasting displays, with almost an hour duration. The image here shows some of the stacked photos of the display. All together I took more than 600 shots.

The formation of elliptical halos is still somewhat mysterious. While good simulations are produced by obtuse hexagonal pyramid crystals having pyramid apex angles of around 175°, the current knowledge of ice physics does not give much support for such a crystal.

The display was formed - as usual - in Altocumulus virga. More on the cloud associations here.

Upper Lowitz Arc in the German Alps

At Oktober the 15th 2005 in southern Germany was one of the greatest Halophenomena, which had ever been observed in Germany. It was photografical documented by six Observers on a latitude of 100 km. There was seen a bright 22° halo, glittering bright sundogs with absolute clear colours and a high part of blue, a complete and bright upper tangent arc, a reddish lower tangent arc, a highly coloured and complete Circumzenithal arc, a light-coloured and nearly complete Parhelic Circle, the complete Lowitz arcs, the Anthelion, the 120 deg parhelia with oblique arcs, a single Superlateral arc, both Infralateral arcs as well as a beauty of Parry arc. Alltogether there were seen 15 miscellaneous Halotypes with 20 appearances.

Lunar halos over Ohio USA

Got this nice lunar display last night.

Latest halo displays from Finland

During the last days series of reasonable displays developed over Southern Finland. Three of them were in moonlight and one in sunlight. Elliptical halo, 9° and 18° halos and Parry arc were observed. See photos and drawings here.

The picture on the left shows the halo developement in Tampere on the night of 14/15 March. Among common halos, faint 9° halo and Parry arc are also present.

Trickers and diffuse Anthelic Arcs in Germany

Alexander Wuensche from Görlitz (southeast Germany) observed and photographed these wonderful Anthelic arcs.

He writes: "In the morning of February 23, 2006, snow stars fell from the cloudless sky. The temperature was 2 deg below zero and there was a slight breeze from northeast. In the northern and northwestern direction the were remains of a Stratus and Stratocumulus cloud layer. In these clouds, the Anthelion with Trickers and diffuse Anthelic Arcs appeared.
The phenomenon was restricted to the direction opposite of the sun. In the direction of the sun I only spotted two small non-spectacular sun pillars."