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The Moon
(lemmy.world)
The Moon just now in the UK. No idea what is creating the halo
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this post was submitted on 25 Nov 2023
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That would be a 22° halo, a fairly uncommon atmospheric phenomenon where light refracts through hexagonal ice crystals in the atmosphere resulting in an average deviation from the angle it comes in at by around (funnily enough) 22°.
There are lots of other interesting atmospheric phenomena including sundogs, moonbows, and the much rarer 46° halo!
Oh nice, I've seen this before in Florida but was unable to capture it in my phone's camera. Didn't realise it had a name!
You're just making things up now XD
Though it sounds silly, sundogs are the name of an actual optic phenomena. They appear as bright spots on either side of the sun, aligned with where the halo may appear. Hence, they are "dogging" the sun.
Yarp, I looked it up. The etymology section is fun, I like to think there's no real meaning behind it, someone just called it that and the name stuck.
No, that’s updog.
If that's the really huge halo that seems to take up most of the sky, I've only seen that perhaps 3x in my life.
Are they not collectively called coronas, in your part of the world? They are here.
Yeah that's the one! Only seen it once (coinciding with a supermoon which was frankly surreal).
Coronas are a bit different I believe, though another one of the same group. I've always just called them their individual names, with coronas being tighter and more spectrally-distorting than halos. Maybe the only other collective name I've heard would be the minimally descriptive "atmospheric phenomenon" but that's no fun at all.
Edit: Just took a brief look and indeed coronas are related but formed by refraction through water droplets rather than ice crystals! Cool to know!
Not refraction, but diffraction and interference. The droplets (or ice particles or in some cases even pollen) get so small that light stops behaving like rays at those scales.
Ahh yes, that's the one! Thank you
Thanks, that's interesting! Colloquially they're just called coronas here I think, but it sounds like a misnomer.