Pyramidal halos 8-14-07

After weeks of seeing no nice halo displays I was at work today on breaktime and I saw 22 halo and upper 22 deg tangent arc. I put my sunglasses on and I soon realized I had an odd radius display at hand. In all there was 9 deg. halo 18 deg halo and the outer halo who knows it could be 22 or 23 or a combo of both. The upper arc is convincing it looks sharp and I think it might be 22deg upper column arc but not sure. One photo is an original and the other has USM applied to make the halos stand out better. This is a good odd radius display for me but I know there is a lot better.

Odd radii in Southern Finland

A horrendously quiet April passed by without any noteworthy action (except Jarmo's fantastic bolide halo). Halo people were awakened from oblivion on 5th May, when a smooth cirrostratus veil crept in from west and offered plate crystals and odd radii halos. The display was seen and photographed by Ismo Luukkonen in Turku, Marko Riikonen in Helsinki (photo on the right by Marko) and Jukka Ruoskanen in Riihimäki.

Most likely all odd radius halos were on the sky, of which 9, 18, 20 and 35 degree halos were easily discernible. The 22-24 region may have consisted of all three possible rings. Also few of the odd radius plate arcs were present, although rather poorly.

Odd radius halos in diamond dust in Finland

On 23 February an another diamond dust display with odd radius halos occured in Vaala, Finland. Temperature was dropping from -29°C to -24° during my observation.

A parhelic circle and circumzenithal arc were present with nice parhelia. A subsun and subparhelia were also seen as sparkling ice crystals in front of the ground.

Odd radius halos labelled in this enhanced photo are A) a pyramidal heliac arc, B1) upper 24° plate arc, B2) lower 24° plate arc and C) upper 23° plate arc.

The most brightest odd radius halo was 18° halo and in some photos there probably are also 9° upper plate arc and 20° halo. The ice crystal cloud was produced by a local heating plant about 2 km away. More photos can be found here.