Ridge Line Induced Crepuscular Rays

October 19, 2010


Photographer: Piero Armando

Summary Author: Piero Armando; Jim Foster

With a fantastic view of the Italian Alps just to the west of where I live, I'm fortunate enough to enjoy many splendid sunsets. The photo above lacks the fine colors that results from many such sunsets but displays an impressive array of crepuscular rays. Since the sky is free of cumulus turrets that often are responsible for rays, they must form in another way. In fact, these rays are due to natural gaps and prominences along the ridge line as well as the presence of dust and haze in the lower atmosphere. These aerosols are very effective in scattering sunlight. It's easy to see just where sunlight is blocked (spurs) and allowed to stream through (notches). Photo taken on September 1, 2010.


Photo details: Canon EOS 30D camera; manual mode; 1/1000 second exposure; F7.1; focal length of 180 mm; image cropped.