Diamond dust season opened in Finland

On October 26 the pupils of the Särkijärvi school near the small northern Finland town of Muonio stopped suddenly their indoor activities and rushed out - somebody had noticed a halo wonder in the sky.

At the school were also excursionists from University of Lapland. Among them, Päivi Linnansaari happened to have a camera handy and took several photos of which a selection is presented here.

The display had all the basic flavourings of a great diamond dust display, including the helic arc, circular Lowitz arc and diffuse anthelic arc - the latter of which is seen faintly in the lower left image. But then there is also a new halo: the 46° contact arcs. Theoretically it has been known for quite a while, but no convincing photographs have come up untill now. The halo shows up in the upper right image as three arcs below the circumzenith arc. Probably a comparison with simulation is needed to get a proper grip of it.

The halo display made it also to local newspaper. Couple of kilometres from the location there is a ski center, so the halos may likely have originated from snow guns.