Halo Around the Moon?

Steve H. · #1 Postby **Steve H.** » Thu Mar 04, 2004 10:51 am

General question for the floor. What really causes it? I always thought it was high-level cirrus running out ahead of an incoming weater system. But then it always seems to be a perfect circle. Is it really the increase of RH at higher levels of the atmosphere? Answers appreciated. Thanks :wink:

https://www.youtube.com/user/senorpepr · #2 Postby **senorpepr** » Thu Mar 04, 2004 11:49 am

Yes, it is cause by cirrostratus clouds, which are found in the upper troposphere. As for why it creates a perfect circle... that's an optical illusion. If you look at your car and it has all those hairline scratches from automatic car washes... you can see the same illusion. Look at your car with the sun overhead and it will seem as if those scratches are all in a perfect circle, pointing to the same center point. Then, move around. The scratches will seem to move to make a perfect circle elsewhere. It's the same principal. Hopefully, someone else can fill in the blank spots on that description.

CThomp8806 · #3 Postby **CThomp8806** » Thu Mar 04, 2004 2:30 pm

I saw one the other night....pretty cool....

Stormsfury · #4 Postby **Stormsfury** » Thu Mar 04, 2004 7:46 pm

Steve, the 22º halo is a perfect circle (since it's always with the 22º halo, located at ... 22º :lol:

), however, there are other types of haloes as well, and I had the priviledge to see the most dynamic and colorful display of haloes just this past Sunday ... I took some shots of those, but I couldn't get the whole perspective of the magnificance of it ...

These haloes included the sun dogs, 22º halo, Suncave Parry arc, Upper tangent arc, Circumzenith arc (the most colorful and prettiest of the haloes) and the supralateral arc, a VERY RARE phenomenon in these parts ...

More information can be found at This website

Also here are some shots I took last Sunday of the haloes around the sun...

This one was taken in British Columbia, Canada by Lynn Fink...

These are a couple I took ... look CLOSELY on this shot, the circumzenith arc is accompanied by the VERY RARE 46º Supralateral Arc (you can see a sliver of color on the left side of the base of the circumzenith arc.

Might be a little easier to see on the thumbnail version ...

Another shot of the brilliant circumzenith arc and faintly viewable supralateral arc ...

Closer to the sun, and under the circumzenith arc lies the faintly lit 22º halo, with the upper tangent arc (sloped like another smiley face) and just above it, a rare colorful suncave Parry Arc ...

#5 Postby **Stephanie** » Thu Mar 04, 2004 8:13 pm

WOW!

Who was it, just a week ago, that said that they saw "sun dogs" as well. That is so fascinating.

Pinwheeler · #6 Postby **Pinwheeler** » Thu Mar 04, 2004 9:43 pm

First of all, the haloes are caused by optical diffraction from microscopic ice crystals in clouds. It is in a sense an illusion like a rainbow is in a sense an illusion, because there is no single object making the ring of light - it's a whole bunch of things causing light to get to your eyes.

Second, is a "sun dog" another name for one of the things previously mentioned, or is it a separate phenomenon?

CajunMama · #7 Postby **CajunMama** » Thu Mar 04, 2004 9:53 pm

Try this link....i found it on a local tv stations weather page

http://home.hiwaay.net/~krcool/Astro/moon/moonring/

Steve H. · #8 Postby **Steve H.** » Thu Mar 04, 2004 10:15 pm

Thanks for the responses folks. And the links and pix!

pawlee · #9 Postby **pawlee** » Sun Mar 07, 2004 9:57 am

excellent captures! below is one of mine...
http://www.pawleewurx.com/pgs/wxp13b.html

Halo Around the Moon?

Halo Around the Moon?

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