Large scale diffraction

While viewing a lake, there was a fallen tree in it and waves heading perpendicular to it. It left a pattern behind it which looked like light diffraction, which is the cause of iridescence and coronae. Diffraction is when waves bend around an obstacle and interfere with other light waves, some cancel each other out and others amplify each other.

Water waves bending around a log

Simulated corona by shining a laser through a small

pinhole

Pileus, Shadows, and Colors 8/17 2010

My dad and I were by the river and were treated with a beautiful sky August 17 last year. There were large cumulus congestus clouds everywhere topped with pileus clouds. Pileus clouds tend to form all at once, meaning the droplets are of uniform size. That means good iridescence! And just that happened, I've not yet seen iridescence as good as this day. After that, long shadows were cast on the upper cloud layer.

Pileus clouds and planes

Beautifully iridescent cloud. This image has

not been enhanced in anyway.

Long cloud shadows