Wednesday, 26 March 2008

Two halo days in the northern part of the Czech Republic

At the weekend of 15 – 16 March, observers in the northern part of the Czech Republic had some opportunity to see rare halo phenomena. On 15 March, in the afternoon, fine cirrostratus came from the west, and subsequently bright halos appeared.

Patrik Trncak took a series of photos of the display. The most uncommon halos that he observed were the Wegener arc, which crossed the parhelic circle; and the Tricker arc, which was noticed afterwards on the images processed by Registax ( 1 ).

The next day, the situation was similar, but the Wegener arc was brighter and the cirrostratus clouds lasted for a shorter period ( 2 ).

I (Martin Popek) didn’t have such good luck but I could also observe some interesting halos. On the first day, a nice suncave Parry arc was visible, which shows well on the stacked images. By the bright parhelia, Lowitz arcs appeared, and after a long period of time I saw an infralateral arc, as well ( 3 - 4 ).

On the second day, the halos were less numerous. There was only one that is not so frequent: a faint 46° halo ( 5 ). Later I observed an interesting lunar display, too, including a diffuse 9° halo ( 6 - 7 ).

Text: Martin Popek, Lukas Shrbeny


  1. What's the sun elevation for Tricker? Don't remember it now but is it also that Tricker separates from parhelic circle in a similar manner as diffuse arcs when sun gets above 32 degs?

    That 9 halo by Martin interesting. Some other halos there making it broader or some artefact?

  2. So good to see these photos, Martin and Patrik. And once again it proves that even though our countries are not neighbours, they are not far from one other. On 15 March a suncave Parry arc was observed here as well, no report of a Wegener and Tricker, though...
    On the very same night we also had a 9° lunar halo, but it was nothing extraordinary; definitely not as broad as in these photos.

  3. thanks.
    9halo to observer by naked eye.
    is see to original picture.

  4. We had a great halo display here in Estonia as well in the morning of the 25th March which lasted a couple of hours. Parry arcs and very well defined supralatereal arcs. Interestingly a strong 22 degree halo lasted over 8 hrs from 9P.M til the approaching snowstorm on 5A.M

  5. Nice display there I got a two hour lone elliptical halo that at times had up to three ellipses.

  6. marko riikonen1 April 2008 at 16:29

    This Tricker is really nice. I have not before seen a photo of Tricker separated from parhelic circle. Moilanen has one moon display from 1996 where diffuse arc is separated in a similar style.