Thursday, 1 February 2007

Combination of high level cloud and diamond dust activity

On the evening of 30th January cirrostratus clouds filled the sky and odd radius halos (9, 20 and 35) were seen in the Moonlight in Hyvinkää, Finland. The 20 and 35 halos were very weak, and couldn't be seen with naked eye. In addition to the high clouds there were good but fast moving diamond dust areas on the ground level. At times the halo display was a combination of cirrostratus and diamond dust halos. In the photo on the left the parhelic circle was caused solely by diamond dust, whereas the other halos were mainly originated in high clouds. A collection of photographs taken by Jukka Ruoskanen is here. 9 degree halo was also seen in Espoo by Timo Kuhmonen, in Helsinki by Marko Riikonen, in Turku by Ismo Luukkonen and in Tampere by Jari Luomanen.

Exciting divergent light halos were photographed as well in Hyvinkää. A more detailed description of the divergent light halos is here.


  1. Wow that is a beauty!!! Thats the first time I have ever saw photos of anthelic arcs from divergent light sources. One thing you may want to try Jukka when you have your headlights and that is to cover one of them so that way you wount get that double effect.

  2. You're right, Michael. I have always covered the other lamp when photographing fogbows or halos until last autumn when I managed to crash the other lamp cover. So, throwing a jacket onto a lamp is not a good idea, since the heat that is generated under the jacket apparently becomes too much. This kind of lamp cover crashing happened to other people in Finland as well, so one would need to be innovative and come up with another method to cover the other lamp.

  3. Jukka I used a piece of cardboard when I did fog bows and the way I did it I simply leaned it against the light and I had no problems with fire or over heating.