Ring around the moon

[domstar]

Hi everyone,

I've just popped out on the freezing balcony and  there are high clouds around. When I looked at the moon, there was a huge circle  of cloud all the way past Procyon and centred on the moon. It's like a giant smoke ring. It looks amazing. Have you seen this effect before and what causes it. It must be something to do with the light of the moon cutting through the high cloud but why such a defined border? Can anyone shed some light as it were.

[Stu]

3 minutes ago, domstar said:

Hi everyone,

I've just popped out on the freezing balcony and  there are high clouds around. When I looked at the moon, there was a huge circle  of cloud all the way past Procyon and centred on the moon. It's like a giant smoke ring. It looks amazing. Have you seen this effect before and what causes it. It must be something to do with the light of the moon cutting through the high cloud but why such a defined border? Can anyone shed some light as it were.

Sounds like 22 degree halo, caused by ice crystals in the atmosphere.

https://en.m.wikipedia.org/wiki/22°_halo

[domstar]

Thanks. If 22 degrees is your open hand at arms length then either I have very small hands, very long arms or it's a 46 degree halo. Could that be possible? I'm awestruck.

Edit- obviously not 46 degrees as it's not centred on the sun.

Edited March 5, 2020 by domstar

[Ships and Stars]

Just saw it literally seconds ago! Was thinking to set up tripod for a photo but putting kids to bed. Not trying very hard admittedly...

[Stu]

7 minutes ago, domstar said:

Thanks. If 22 degrees is your open hand at arms length then either I have very small hands, very long arms or it's a 46 degree halo. Could that be possible? I'm awestruck.

I think it is a 22 degree radius so 44 degrees in total... does that make more sense?

EDIT although it is much more fun imagining you with little teeny tiny hands dragging along the floor on very long arms 🤣🤣

[domstar]

Ha. yes 22 degrees radius not diameter. Never seen it before. Amazing.

[Stu]

1 minute ago, domstar said:

Ha. yes 22 degrees radius not diameter. Never seen it before. Amazing.

Good aren't they. They are also associated with Sun and Moon Dogs which form at the same position

https://en.m.wikipedia.org/wiki/Sun_dog

[Pete Presland]

They do look very cool, i saw this one a few years ago from my back garden.