Observed phenomena: Halo phenomena
Light source: Sun
Origin: High clouds (cirrostratus)
Observed halo forms:
- 22° halo
- Upper tangent arc
- Lower tangent arc
- Upper 23° parhelia
- 18° parhelia
Observing place: Turku, Finland
Observing method: Photography
Technical information about photographing equipment: Olympus μ 1030 sw
On 16th of May 2013 I noticed a diffuse -looking upper tangent arc in the sky of Turku. I observed that halo for several hours, and then I thought that perhaps it is not an ordinary upper tangent but an upper 23° parhelia. I’m pretty convinced, that there was also an ordinary upper tangent arc, because I observed also a lower tangent arc in the sky. For a short while, I observed also a weak 22° halo. In the photos, that I took at 16:00, there was also a short arc-like spot in upright position. I interpret, that it could have been a 18° parhelia.
The upper 23° parhelia -interpretation gets support from other observations from Finland on that day. On 16th of May 2013, many observers reported pyramide halo sightings from many localities in southern Finland.