Odd radius halos in Finland

Yesterday, 6 May 2006, odd radius halos were observed in a large area in Eastern and Central Finland. Odd radius halos observed during the day were mainly circular halos and plate arcs.

I photographed the display in Vaala, were it lasted for 3 hours. Photo shown here is made by stacking 24 photos which were taken during 10 minutes time. Unsharp mask has been used to show halo better. Visually halos of the display were not as clear as in this stacked photo, but all halos shown in this photo were also observed visually, except 35° halo which can be seen faintly on left. More photos are here.

Jenni Holopainen in Joensuu probably got best odd radius halos during the day. Her photos can be seen here and here. Marko Mikkilä observed odd radius halos in Nivala, Teemu Öhman in Äänekoski and Eero Savolainen in Kuusankoski. Photos by Mikkilä and Savolainen can be found also here.

Ice Crystals

"Atmospheric Optics" has a newly updated section about halo forming ice crystals - check under "What's New". Plate, column and pyramidal crystals are illustrated with their orientations and resulting halos.

Off topic - A new Atmospheric Phenomena blog

Following the idea of Halo reports blog, a new Atmospheric Phenomena blog has been opened by Claudia Hinz. There will be reports of of recently observed interesting atmospheric phenomena around the World. Reports will cover all other atmospheric phenomena except Halos. Halos will be reported here in Halo reports blog.

Atmospheric Phenomena blog can be found here.

Diamond Dust Halo in Austria

This picture was taken on December 10, 2005 by Wolfgang Gurgiser at the summit of the Hohe Salve (1829 m, Kitzbühler Alps, Austria) at a temperature of about -7°C. Contrary to what is usual, this halo was not caused by cirrus clouds, but by diamond dust which had direct contact to the ground. This diamond dust consisted of needle-shaped ice crystals smaller than 1 cm.

Besides the 22°-halo, the picture also shows a V-shaped upper tangent arc and Parry arc, the arc of Moilanen which is also V-shaped and situated at 11° above the sun, and – emanating from the sun – the heliac arc.

Complex display with odd radius column arcs in Finland

A long-lasting halo display was seen in Southern Finland on 25th April. The gems of the display were odd radius column arcs, of which 9, 20 and 24 degree arcs were seen. Additionally, 9 and 24 degree lower plate arcs as well as an 18 degree halo and possibly a 23 degree upper plate arc were visible for a short period of time during the day. The duration of the display was spectacular; for instance the Wegener anthelic arcs and 120° parhelia were continuosly on the sky for almost three to four hours. At the latter stages of the display a beautiful 46° supralateral arc and magnificent circumzenith arc appeared. The display was photographed by many people - Marko Riikonen in Helsinki, Jari Luomanen in Tampere, Lauri Kangas in Espoo, Marja Wallin in Lahti, Timo Viinanen in Hameenlinna and Jukka Ruoskanen in Hyvinkaa.

Elliptic halos over Deventer

Predominantly incomplete but brightly colored elliptical halos over Deventer, the Netherlands on Sunday 23/4. The display occurred in two stages, the first performing one elliptic halo section (vertical radius app. 5degs) from 1030-1037 UT, the second from 1048 to 1100 UT, during some minutes including a fainter and smaller but complete inner elliptic halo (vertical radius app. 3degs). By the time shape was somewhat varying. Most striking was the coloration, with dominating red to orange but also yellow and blue outside. Sun elevations were 48.3degs at 1030, and 49.6degs at 1055UT.

Tranquility of a high-sun halo display

This fairly decent high-sun display was captured while I was on lunch break. Although there were no rare halos but there was 22d halo, circumscribed halo, smooth complete parhelic circle, and faint circumhorizon arc. The best part in my opinion was the parhelic circle. I have applied unsharp mask to bring the halos out better. Photos were taken on the 11th.