Superb diamond dust display in Austria

On 18 October 2010 a superb diamonddust halodisplay was observed at the meteorological station Sonnblickobservatorium ( 1 ) in the Austrian Alps (3106 m, 12°57’ E, 47°03’ N). Hermann Scheer, member of the meteorological team at the observatorium, took images of 13 different haloforms between 08:30 and 09:00 CEST (06:30 and 07:00 UT): parhelia, 22°-halo, 46°-halo, lower tangent arc, subsun, subparhelia, infralateral arc with Parry-infralateral arc, supralateral arc, parhelic circle, subparhelic circle, subhorizon Wegener arc and helic arc. ( 2 - 3 - 4 - 5 - 6 ) The images were taken at a sun elevation of 8,9° to 10,3° between 08:31 and 08:40 CEST, the file names indicate the exact time.

The brightness of the Wegener arc was incredible. Very interesting is the combination of Parry-infralateral arc with infralateral and faint supralateral arc. This part of the phenomenon is similar to an observation in the Czech Republic (26th of December, at Lysa hora in Krkonose (Giant Mountains)), described at Optické Úkazy v Atmosférè ( 7 - 8 ) Thanks to Tomas Trzicky for the links. And also in Ice Crystal Halos ( 9 ). In this very small area of the display we can see a 46°-halo, Wegener arc, helic arc and the subparhelic circle too.

The display was observed at the upper boundary of the stratiform layer; weather conditions: 06:00 UT - air temperature -6,8°C, air relative humidity 96%.

Credit to Hermann Scheer for giving the permission to show his images at Crystal Halos Blog under this licence: ( 10 ). Homepages of Hermann Scheer: ( 11 - 12 - 13 ). This diamond dust display is described on the page "Atmospheric phaenomenons observed in Austria" too: ( 14 )

Karl Kaiser

Wegener from Altai Krai

The photo of these Wegener-arcs was taken in the Siberian Altai Krai by Alexander Kostenko on 12 August 2010. Further images can be seen in his album ( 1 )

Hungarian odd radii

These odd radius rings and arcs were photographed on 24 July 2010 by Róbert Rosenberg in Adony, Hungary. The photos were taken a few minutes after 14:35 CEST, and about two hours later. ( 1 )

Moilanen arc without snowguns

I was recently filing images digitized from somewhat older slides and came across this upper tangent arc image from many years ago, in the early morning from here in Calgary. I decided to subject this image to some processing, in particular, embossing the image in Photoshop and low and behold, a faint Moilanen arc showed up, as you see in this composite image!

I certainly do not live anywhere near to a ski slope or factory chimney that would produce lots of ice crystals. There is no evidence on the photo of local ice crystals as we see often in diamond-dust displays. The climate here is very dry and we often find low-lying layers of diamond dust particularly over our river.

Thus, I hesitate to claim that this is a "natural" Moilanen arc but it was not taken near to ski slopes. Maybe our furnaces produce the requisite crystals sometimes, in which case I will be on the lookout next winter for a repeat of this display.

Alan Clark

Odd-radii again

Alan Clark sent the above image, which shows the same display that Elmar Schmidt saw from Virginia, and which can be read about in the previous post. Alan photographed the halo from Dulles Airport, about 120 km NE of Elmar's site. The Sun elevation was about 58 degrees, and it was between 15:00 to 16:00 local summer time. As Alan says: "The display was not perhaps as clear as Elmar's in that some components of the odd halo were not distinct." ( 1 )

Alan has sent another pair of odd radius halo images. These were taken from Calgary, Alberta, Canada in May, 2009. ( 2 - 3 )

Pyramidal halos in central Virginia

Elmar Schmidt was travelling southwards after the 10th Conference on Light and Color in Nature in Maryland. He observed this spectacular pyramidal halo display in central Virginia on 22 June. The display lasted for at least 2 1/2 hours and showed several odd radius halo rings and their tangent arcs.

As Elmar Schmidt tells: "All in all the phenomenon looked spectacular and eery with the broad belt starting at the 18-deg-radius. Of note is also its quite southerly location and the longevity, which might be interesting to compare with simulations, especially at the sun's elevation of 57 degrees." ( 1 )

Further images of the display between solar altitude 54 and 29 degrees are also available ( 2- 3- 4- 5 )

Odd radii from Italy

Marco Candotti sent these photos from Italy. The images were taken on 15 June. The 22 degree halo lasted about an hour, while the pyramidal crystal halos only a few minutes. For a short time, a 120 degree parhelion was also observed