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Tag Archives: optics

Partial 22° halo and CZA

Partial 22° halo and CZA by slitherjef
Partial 22° halo and CZA, a photo by slitherjef on Flickr.

On my way home from work tonight I took notice of a partial 22° halo around the sun. When I got home I decided to go ahead and shoot the incomplete halo, thinking the rays would be a nice effect as well.

Well, I got a couple shots off and seen a little bar of color near the zenith (strait up). The sun is pretty low about 90 minutes or so from sunset. Which could be why the circumzenithal arc (near the top of the frame, pink on the bottom and light blue on the top) above the halo is so dim and small.

One other possibility is the arc is part of a much larger halo, the 46° halo, but those are rare and huge.

While this is far from the best example of a circumzenithal arc or “CZA” this is one of the best ones I have managed to photograph. I did kind of push the processing on this photo a bit to help bring out some details. A circular polarizer was also used

Here is a link about solar altitude and the brightness of CZAs: http://www.atoptics.co.uk/halo/czasalt.htm

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Posted by on April 30, 2011 in Atmospheric optics, Photos, Weather

 

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Rays, Rainbows and Rain

Well, we finally got some half way interesting weather rolling through Denver today, a brief thunderstorm in the afternoon and one that missed me earlier in the day. The first cell that passed over us today had some neat structure on its base but I failed to get to it in time. I did get some shots of the anvil after it passed over and headed out of town. The later cell proved a bit more interesting for me, producing a rainbow that did not last too long.

Rainbow

Rainbow over the Pond

 

Since the storm passed by near sunset, some interesting colors started to show, at one point, the thought of, “this looks like root-beer” crossed my mind.

Storm Cell

Storm Cell near sunset

 

Of course, the sun did go behind the cloud that did not do the Rainbow any good, something more spectacular showed up in the west: Crepuscular rays.

Crepuscular rays

Crepuscular rays Over The Rockies

 

Not too shabby, I think since I was stuck at work while this was going on. The key is, to time your breaks just right. The thunderstorm produced some very nice lighting which was helped by the sun which was getting ready to set.

 
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Posted by on April 19, 2011 in Photos, Weather

 

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