Fogbow Over Viterbo, Italy
March 27, 2019
Photographer: Marco Meniero
Summary Authors: Marco Meniero; Jim Foster
Shown above is a conspicuous fogbow or cloud bow as seen from the airport observation tower at Viterbo, Italy on March 4, 2019. Whereas rainbows are formed by raindrops that are sufficiently large to allow light rays passing through them to follow well defined geometrical (optics) paths, fogbows are formed by tiny fog droplets that act to diffract or deflect sunlight. Thus, they're slightly broader than bows that result from raindrops and are generally devoid of color since light rays of differing wavelengths, responsible for color, extensively overlap. Note that this fogbow forms nearly a circle as do all bows that are observed when the horizon is well below eye-level.
Photo Details: Eos 1DxMk2 camera; fisheye EF 8-15/4L lens.