Thursday, 2 February 2017

Subparhelia and sub 120° parhelion on ice surface

average stack of 15 frames
In the morning after new year's night, I noticed through a window cirrus clouds, and I went to observe. While I was waiting for the appearance of halos, I noticed weak subparhelia on the ice surface. Out of curiosity, I decided to look for a place where they could be brighter, and I found it (1, 2). It was quite a small area near a coast, almost all sides limited. There I saw not only bright subparhelia, but also clearly visible sub 120° parhelion in pillar form.

maximum stack of 3 frames
It was perfectly visible even when I did not move. The temperature was negative only at night until this morning. In the previous day it was positive (around +4 degrees of Celsius), as during of the observation (0...+1). 

At that time, while I was shooting halos on the ice surface, in the sky appeared parhelion and 22 degree halo (3). Later the upper tangent arc was spotted in cirrus clouds (on the stack also well visible supralateral arc - 4). At the end of the day, I also noticed weak and wide circumzenithal arc (5) from low sun.

Date: 2017-01-01


  1. Good observing and good work. Jari Piikki observed somewhat less conspicuous sub-120° in similar looking circumstances in 2008:
    There was also subanthelion.

  2. This is a wonderful observation! I remember how much we were looking for sub-120° parhelia when we were in Himos with Marko Riikonen and shot these subparhelia on ice, but could not see them at all:

  3. I had forgotten about that part. But of course you have to look for them. What I remember was that I took a little refreshing dip through that thin ice a before we saw the subparhelia. Just the feet, it was shallow there. And when we continued driving I taped the wet shoes on the car ventilator. They dried pretty quick.

  4. Yeah, I remember your dip. It looked quite frightening, though the drying shoes and socks looked really funny. Halo-hunting has its risks ;)


  5. Thank you Agnes, Marko.

    I already saw those two displays. I thought about them during my observation. Therefore, despite the fact that the ice was not very strong (as can see in photos from the post, the ice near the shore is almost absent), I tried to observe being on its surface. I wanted try to see subanthelion or sub-CZA, but I failed. I only noticed a funny parhelion on a single plate of ice -