Helpful Posts Helpful Posts:  0
Results 1 to 6 of 6

Thread: Circumzenithal Arc

  1. #1
    tybrad's Avatar
    Join Date
    Nov 2012
    Location
    Maryland, USA
    Posts
    144
    Real Name
    Tyler

    Circumzenithal Arc

    I am fascinated with atmospheric phenomena. As is usual, they are best pinned to something Earthly, so I framed with a gnarled pine nearby.

    Here is one- a circumzenithal arc. They are a bit unusual since they arc AWAY from the solar point and arise from refraction of sunlight through horizontally-oriented ice crystals, generally in cirrus clouds, rather than from raindrops. It forms no more than one-quarter of a circle centered on the zenith and on the same side as the sun. Its colors are from blue on the inside to red on the outside of the arc. It is one of the brightest and most colorful solar halos. Its colors are purer than those of the rainbow because there is much less color overlap in its formation. The first impression is that of an upside-down rainbow.

    C&C welcomed.

    1.
    Circumzenithal Arc

    2.
    Circumzenithal Arc

    3.
    Circumzenithal Arc
    Last edited by tybrad; 15th November 2012 at 11:37 PM.

  2. #2
    Moderator Dave Humphries's Avatar
    Join Date
    May 2008
    Location
    Windsor, Berks, UK
    Posts
    16,748
    Real Name
    Dave Humphries :)

    Re: Circumzenithal Arc

    A very educational series Tyler

    Well done,

  3. #3

    Join Date
    Jan 2009
    Location
    South Devon, UK
    Posts
    14,518

    Re: Circumzenithal Arc

    The second image certainly brings everything together as a good scenic shot.

  4. #4
    MilT0s's Avatar
    Join Date
    Sep 2011
    Location
    Athens, Greece
    Posts
    719
    Real Name
    Miltos

    Re: Circumzenithal Arc

    Ah, new knowledge combined with nice photos!

  5. #5
    gcowan's Avatar
    Join Date
    Jan 2011
    Location
    Sydney Australia
    Posts
    290
    Real Name
    Graham

    Re: Circumzenithal Arc

    Hi Tyler,

    Thanks for the image and information. I never knew that was what it was called, I thought it was still called a rainbow.
    Interesting though is that when I looked at the one I photographed a couple of weeks ago in the Kosciuszko National Park it was upside down compared to yours. Now I know that we are in the southern hemisphere but that surprises me as I thought we are looking at a refraction pattern of light which doesn't have an up or down. I will have to do a bit of re-thinking....

    Circumzenithal Arc

    I only took casually because it was there when I was doing something else thinking it would be good for a collection of sky for blending into other images later. I didn't really know how best to process it but this was how I saw it. I had a 70 - 200 lens on at the time and I could only get this much.

    Graham

  6. #6

    Join Date
    May 2012
    Location
    northern Virginia suburb of Washington, DC
    Posts
    19,064

    Re: Circumzenithal Arc

    I like the first image best and especially appreciate the explanation.

    A polarizer will enhance or completely eliminate a rainbow, depending on the position of the filter. Am I right that the same thing would happen when using a polarizer to capture a circumzenithal arc?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •