Crepuscular/Anticrepuscular Rays

Always view the Sun safely!
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Christopher K.
Posts: 5944
Joined: October 12th, 2009, 3:28 pm
Location: Baton Rouge, LA

Crepuscular/Anticrepuscular Rays

Post by Christopher K. »

Today's APOD is of a beautiful phenomenon. I'm wondering if I've ever seen it; I guess if I have to wonder the answer's "no".

Crepuscular and anticrepuscular rays are the same rays. When viewing "coming out of" the Sun they are "crepuscular" and when they head over the opposite horizon one adds the "anti-". Of course, at the opposite horizon they look as though they're shooting over one's head from there as well.

A good situation in which crepuscular rays can appear is when clouds partially obscure the sunlight.

The image (complete with wind farm) by Nate Cassell:
http://apod.nasa.gov/apod/ap120221.html

More information:
Seeing the Sky by Fred Schaaf, pp. 98-99.
Christopher K.
Posts: 5944
Joined: October 12th, 2009, 3:28 pm
Location: Baton Rouge, LA

Re: Crepuscular/Anticrepuscular Rays

Post by Christopher K. »

Earlier this month John Rummel caught an astounding coincidence--crepuscular rays that traced back to the center of a rainbow! The event occurred in Utah's Bryce Canyon. The effect is hard to put into words...the shadowy streaks and the rusts and clays of the canyon below. I wonder if it was the so-called "blue hour" when the image was made.

28 July APOD:
http://apod.nasa.gov/apod/ap150728.html
Christopher K.
Posts: 5944
Joined: October 12th, 2009, 3:28 pm
Location: Baton Rouge, LA

Re: Crepuscular/Anticrepuscular Rays

Post by Christopher K. »

On the evening of 15 September I was leaving HRPO for a short period. Driving out to the front of the property I saw a nice set of crepuscular rays streaming up from the Sun, which was behind a group of trees. I took a picture.

Crepuscular rays were the number eight choice on Jane Houston Jones' countdown list in the "What's Up for October 2015" video.
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