r/atoptics • u/skidpickle • 14d ago

Fun in the sun

Post image

Halo and sundog on way to Sydney from the Gold Coast

37 Upvotes

95% Upvoted

9 comments sorted by

3

u/Metacomet99 14d ago

Interesting to see a 24 degree parhelion instead of a 22. I can't find very much information on this.

2

u/skidpickle 14d ago

I would love to hear more about this!

5

u/Metacomet99 14d ago

Here it is.... yay! It is about solar elevation.

https://www.atoptics.org.uk/halo/dogalt.htm

2

u/skidpickle 14d ago

Oh wow thanks!

2

u/Nekathe 10d ago

woah, this is so cool. I guess you learn something new every day!

2

u/Metacomet99 14d ago

Yeah, it was a while ago when I read about it, something about sundogs usually appear at 22 degrees unless this-or-that, maybe it was something due to solar elevation. arrrgghhh.... if I find it I'll post it. And by the way, this one here has the start of a nice circumhorizontal arc. Maybe that's the missing element.

1

u/Weather_Only 14d ago

How do you tell it's 24 degrees lol

3

u/Metacomet99 14d ago

Just that the larger circle is a 22 degree halo and the parhelia is just a smidge further out. I've seen 24 degree parhelia mention before elsewhere but now I can't find it.

2

u/Gravitaryus 11d ago

Maybe Circumscribed Halo