Wednesday, 17 June 2020

High Quality 28° Arcs in Ji'an, China

Moments before sunset on June 17 2020, a high quality odd-radius plate display with bright and vivid 28° arcs was documented by multiple observers in Ji'an, Jiangxi Province, China.

© HUANG Qian, shown with permission. Single exposure.

© ZHOU Ling, shown with permission. Single exposure.

Annotated version as follows:

The intensity of the display rivals the 2016 Chengdu display as the 28° arcs stand out even in smartphone photos above. 20°, 24° and 35° plate arcs in the photos are also quite well defined.

Unfortunately, like previous displays, no other exotic arcs are found in the photos we received from the community.

Now that we have a great and early start of the season, let's hope for more great stuff to come.


  1. I hope someone will get the lower arcs. This display should of been stacked

    1. Nowadays we're left with only smartphone photos in most high quality cases. DSLRs are pretty much a dying thing now among general public here as smartphones improve. Sad but true :(

      One can only hope mobile camera technology reaches DSLR standard some day.

    2. Here we go again. Another low sun Lascar display! I have been long wondering whether people should start paying more attention to near horizon sun situations concerning the odd radius plate arcs. I think it would be fruitful to check the sun set if there have been odd radius halos in the daytime and clouds are still hanging around. If the display is weaklish, there may be a haloless looking situation at low solar elevations (23 upper plate arc already gone and 18 plate arcs maybe messed up by clouds), but right at the sunset the 20 and 35 upper parhelia suddenly appear out of nowhere because they greatly gain intensity then. And who knows, 28 plate arcs might accompany.

    3. Your observation is in line with ours Marko. Our past few sunset displays only reach visual threshold at low solar altitudes when 20° and 35° plate arcs pop into view. The 28° stuff always show up later and intensify when the sun nears the horizon. It almost seems that the 28° ray path is more sensitive to incident angle than the 20° and 35° plate arc ray paths, and works only when rays enter horizontally.

  2. Guess there is no way then but to go waiting for those sunsets this summer. In Finland it will be the evening. During warm weather periods the pyramid crystal clouds appear in the daytime (many times they look to me like they are forming right there, not drifting in from anywhere) and they may last until evening. In the last photo we took at Lascar, when the sun is already below horizon judging by the redness of the halos, the 20, 28 and 35 uppers really improved from the previous photo, where the sun was 1.6 degree above the horizon. The most solar elevation sensitive halo was the upper 35, it was the only one of the triplet that appeared only in the very last image. It might be possible, though, that it is not seen in the earlier photos because of underexposure.