Friday, 24 March 2023

Odd Radius Display Including 13° Halo, Vilnius, Lithuania 18th March 2023

The display occurred on 18 of March and I observed it from Vilnius, Lithuania.

For the whole day, cirrostratus clouds covered the entire sky. The clouds were moving eastward and also sublimating.

I started observing at 10:25 EET. At that time there were already odd radius halos present: with the naked eye, you could definitely notice both the 9° and 18° halos.

At 11:45, only the 9° halo was present, and at 12:00 the odd radius halos disappeared. After that, and until around 17:00, there were a faint 22° halo and tangent arc visible.

I photographed the halos in raw format with a DSLR camera. After enhancing the images, a 35° halo became visible, but I was surprised the most to see a ring between 9° and 18° halos, which appeared to be a 13° halo. After sending the images to The Halo Vault, I got a confirmation about this from Nicolas Lefaudeux and the Halo Vault team.

Here are some pictures from the display, last two of them in the sequence were processed by Nicolas Lefaudeux:

(All images copyright Donatas Gražulis)









(Image processed by Nicolas Lefaudeux)

(Image processed by Nicolas Lefaudeux)

A similar feature appears in an older photograph that I took on 25 of June 2019. This is the only photo from that day that this appears in; it was taken with a phone:




- Donatas Gražulis

Thursday, 9 March 2023

Unusual Elliptical Halos May 8th 2022 in Japan


On May 8, strange elliptical halos were captured by Pipibun in Kunimi, Fukushima prefecture, Japan.

At 14:30 that day, there were cirrus and cirrostratus clouds in the sky, and some frequent halo forms appeared. After taking pictures for a while, the observer moved about 20 km to the north. 


At about 16:10, looking at the sky again, altocumulus clouds over the sun and the double elliptical halos appeared above it. The display lasted for 20 minutes. With the sun 23-26° high, major axis of outer ring was about 10° and minor one was 5°. 

The shapes of the elliptical halos are varied and are thought to be affected by apex angle of the flat pyramidal crystals (or possibly dendritic snow-type crystals.) Additionally, they are known to become sometimes multiple and inner rings are basically similar ellipsoid. Therefore, were there at least two different gradient responsible crystal groups in that sky?