Astronet forum

Peter R wrote:Jag har läst kommentarsfältet på https://www.taivaanvahti.fi/observations/show/79745" onclick="window.open(this.href);return false; men förstår inte riktigt vilken som är den nya halokomponenten.
Kan någon specificera / peka ut den, exempelvis i Les Cowleys annoterade version?

Hello Peter,

Good to hear from you again.

That display (even though it came from snow blower nucleated crystals ;-) ) must go down as one of the great ones.

The two green halos are real. I had already labelled on my site the ones going upwards from the parhelia. They are reflected lowitz arcs:
https://www.atoptics.co.uk/fz380.htm" onclick="window.open(this.href);return false;

The arcs inside the circumzenithal arc are continuations of the ones I have labelled as 46 degree Lowitz arcs. These arcs are exceeding rare and arise from rays passing between hexagonal and side faces of Lowitz oriented plate crystals. The continuations cross the CZA and the two 'strands' inside do not form a circular arc. I've attached a marked image to better show what I mean!

Two halos that I did not label are perhaps the most exciting. These are the fuzzy bright areas above each parhelion at the same altitude as the upper tangent arcs. These are probably 'parhelia tangent arcs' arising from rays passing through two crystals - plate crystals and column crystals. 44degree parhelia - https://www.atoptics.co.uk/halo/44pars.htm" onclick="window.open(this.href);return false; - arise in the same way. These 'secondary halos' demand very high concentrations of crystals. I was rather unsure whether they might instead be cloud streaks when i made the OPOD but the Finns have since confirmed them.

All the best,
Les

Katarina H wrote:Såg att Jennifer Andersson på Populär Astronomi skrivit artikel om detta. Lång och detaljerad artikel men astronet nämns tyvärr inte, annars var den bra

Katarina