Monday, 29 January 2018

Surface Halo Arcs on Icy Puddle

Surface halos were observed on frozen puddles by Hungarian observer Dávid Hérincs. He photographed the halos on the morning of 25 January at about 10° Sun elevation. As he reported, with naked eyes he could only see the glittering of ice, the halos came out only afterwards in the photographs. Besides the subsun and subparhelia, sharp halo arcs were also photographed which look like lower tangent or Parry arcs. Can anyone provide some explanation for what exactly these are? More images.

Photo of a similar phenomenon by Dávid Hérincs from 30 December 2016.

Friday, 26 January 2018

Elliptical Halo January 25th 2018

Following my recent observation of subparhelia and sub-PHC on the car windshield earlier in the week, yesterday I had another great catch. Whenever I see altocumulus clouds the first thing that comes to mind are elliptical halos. A large patch of blue sky appeared and looking up, sure enough there was an elliptical halo! I brought the camera and I took a bunch of shots of the halo some of which I present here. I have a feeling the 2018 halo and sky optics season is going to be a good one.

Thursday, 25 January 2018

Testing the spotlight

This year's winter in the Czech Republic is very mild. Only three situations occured with enough moisture and deep enough temperatures for halos to form. January will be most probably somewhere around 3°C above normal. NAO (North Atlantic Oscillation) is most likely responsible - with it being well in the positive values, constant flow of low pressure systems from the west hinders any chance for very cold continental air to move in from the east. While this mode brings fairly moist oceanic air, temperatures oscillate around zero degrees Celsius, which does not correlate with halos.

On December 29th, 2017 it was different. Rather cold and moist air settled in the Czech Republic, influenced by a low centered in Scandinavia and high pressure ridge from the SW. As the temperatures were dropping well below zero degrees Celsius, I decided to keep an eye on the cameras in case something was happening.

And it sure was. A few hours after the sunset, they started the snow guns at Kyčerka ski centre. Only a few moments later, bright and glistening upper tangent arc could be seen extending from a strong lamp situated at the ground level of the ski slope.

I decided not to waste any time and quickly packed my gear along with a new spotlight and headed for the ski centre. I "packed" a friend with me, too.

An interesting addition - the route for the ski centre begins rather tediously, leaving the town of Ostrava and heading for the glorious mountain ridges and crests of the Beskydy mountains. As you're approaching, beautiful scenery opens up. The brighter the Moon and the larger the snow cover the better.

This is a picture of one of the many ridges, lit by an almost full Moon. It was taken at a different time, while also heading for halo hunt.

To arrive at Kyčerka, you have to drive over some of these ridges. And as we were at the highest point of our journey, we eventually drove through cloud cover. Only waiting for some nucleating agent, as the temperatures were somewhere around -6°C.

We were only 2 kilometers away from our destination and at Jezerné (a much smaller ski slope in Velké Karlovice) the halos already started.

At our destination Kyčerka, the snow guns were on full blast. And even though the cloud cover we drove through previously only hovered above the highest peaks, well far away from Kyčerka, soon the crystals developed and began to swallow the whole valley of Velké Karlovice in a thick ice fog. For the first time ever I've experienced the marvelous glints in a bright spotlight.

Unfortunately though, the temperature didn't drop much below -10°C, so plates were almost non existant. There were glints where parhelions are supposed to be, and in the photos some brightening at the left and right sides of the 22° halo are visible, but it wasn't enough to produce major light pillars, CZAs or others.

I am a little bit scared that there may be only one situation ahead - the temperatures are forecasted to drop at the end of January, but I don't think it will be any different. So it doesn't seem like I will be the first one in the Czech Republic to hunt the Kern arc. Or at least.. not yet!

Monday, 15 January 2018

Halos on windshield

Tonight there was a diamond dust display that had parhelia and pillars. Later I went back out and happened to walk past my Dad's car where I saw a long curve of bright sparkles on the windshield. I took a closer look and saw subparhelia. I got my flashlight out and that is when the fun began. I placed the light on the hood and got bright, colorful and clear subparhelia along with a diffuse subparhelic circle. I also held the light high above and got circumhorizontal arc as well. The diamond dust I kind of messed it up with the lens being slightly out of focus. I didn't realise this until I got to look at the pics on my screen.