Sundogs Monday Morning

 

Click here to see how sundogs form.

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This post was written by Schnack on January 27, 2014

Halo Around the Sun

The photo below shows a halo around the sun. It was taken this morning by Kathy McCoy.

Halo

The image below shows a halo around the sun in addition to a sundog on the left side. The sundog on the right is not there because of clouds. The photo was taken by Danny Murphy.

1

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Posted under Optics, Photo

This post was written by Schnack on January 21, 2014

Moon Dogs and Sun Dogs

In the last 24 hours we have had the chance to see a lot “dogs” in the sky. In the last few weeks Sun Dogs have been seen. Something that is not as common is a Moon Dog. The Moon Dogs are formed the same way as Sun Dogs are, but the light source is the moon not the sun. Jan 17 Moon Dogs Jan 17 Sun Dog

 

Click here to see how the “dogs” form.

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Posted under Optics

This post was written by Schnack on January 17, 2014

Sundogs This Morning

Click here to see how sundogs form.

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This post was written by Schnack on January 6, 2014

Light Pillars

When you were out this evening did you see the lights “shooting” up into the sky? Those are called light pillars. They form as light is reflected by horizontal ice crystals. Here is photo from Josie Petersen taken in Cedar Falls.

Dec 30 Light Pillar

 

The photo below is from East Dubuque, IL taken by Lori Junk.

Dec 30 Pillar 34

Click the image below to get a more technical description as to how they form.

Dec 30 Pillar 2

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Posted under Optics, Photo

This post was written by Schnack on December 30, 2013

Sundogs Monday, December 23

Click here to learn how sundogs form.

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Posted under Optics, Photo

This post was written by Schnack on December 27, 2013

Sundogs Today

I have many photos sent to me each day on my Facebook page, Twitter and by email. Today most of the photos were of the sundogs seen this morning and this afternoon.

Here is the short answer as to how they form. Sundogs are the “rainbow” like lights on either side of the rising sun or setting sun. The sun needs to be low in the sky. So that means the best time to view sundogs would early in the morning or late in the afternoon. There also needs to be  high thin clouds (cirrus) overhead. The cirrus clouds are made of ice crystals.  The crystals refract the sun’s rays.

Here is a link for the more technical answer to how they form. Click here

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Posted under Optics, Photo

This post was written by Schnack on January 31, 2013

Cloud Shadow but in the Sky

The photo above was taken by Dan Gingerich. It is the Hot Shot photo at 5 pm today. It was taken in Decorah. I was not sure exactly why the shadow looked the way it did in the sky. When it comes to atmospheric optics the #1 source is Les Cowley. He runs a GREAT web page. http://www.atoptics.co.uk/ 

I have asked him questions before and he ALWAYS has the answer. So I went to him again to help me out. Here is what he had to say about the photo above.

Cloud shadows and rays can, like these ones, be very counter intuitive! 

The dark shadows look like they are pointing upwards but in reality they are angled downwards – all shadows cast by the sun must go downwards.      

There is a thin layer of hazy cloud _below_ the top of the towering cumulus.    The sun is casting a shadow of the cumulus cloud onto this lower layer.   We see the shadow through the other side of the lower cloud layer ‘screen’.     The shadow looks above the cumulus cloud simply because the shadow is closer to the camera.   See the diagram here: http://www.atoptics.co.uk/atoptics/rayim13.htm

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This post was written by Schnack on January 17, 2013

Lunar Halo Sunday Evening

The photo below was taken by Jenn Palmersheim Sunday evening.

The ring around the moon is called a halo and since it is around the moon it is a Lunar Halo. The reason for the halo is because there are high thin clouds moving between Earth and the Moon. Click here for more information  halos.

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Posted under Optics

This post was written by Schnack on November 25, 2012

Circumhorizontal Arc

The photos below were taken on Tuesday May 15 during the afternoon. I contacted Dr. Les Cowley (an optics specialist) to explain the photos below. Here is what he had to say.

The first 2 photos are ice halos –  circumhorizontal (preferred circumhorizon) arcs.    

There is a widespread Internet myth that these are very rare and on those sites they are erroneously and misleadingly called ‘fire rainbows’.   They are not rare.   In the US you can expect to see several each summer if you watch the skies They are formed by plate crystals in cirrus.   More about them in this site section:
http://www.atoptics.co.uk/halo/cha2.htm

Taken by Kevin Bublitz

Taken by Yeni Klemesrud

Here is what Dr. Cowley has to say about the photo below:

This photo is much more interesting and its a relatively rare shot.

The camera is pointing almost straight upwards.   The colored arc at top is the common 22 degree halo around the sun ( http://www.atoptics.co.uk/halo/circular.htm ).   The mid-frame white circle is another ice halo, the ‘parhelic circle’.   This halo circles the sky always at the same height as the sun.   When the sun is high – as here – it shrinks in size but remains centered on the zenith.   See:
http://www.atoptics.co.uk/halo/pchigh.htm

And a section about the parhelic circle - http://www.atoptics.co.uk/halo/parcirc.htm
Taken by Yeni Klemesrud

Click here to check out the optics web page that is run by Dr. Les Cowley.

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Posted under Optics, Photo

This post was written by Schnack on May 17, 2012