Spout Bow

March 17, 2015


Photographer: Jim Grant
Summary Authors: Jim Grant; Jim Foster

Spout Bow2

March 2015 Viewer's Choice






The photo above shows a gray whale spouting a faint rainbow. It was taken about 2 mi (3.2 km) off Point Loma, California, on the morning of February 6, 2015. In January and February whales are seen every day here as this is part of their winter feeding and nesting area. On any sunny day spout bows can be seen here as long as the Sun is at your back. The photo at left showing a surf bow was taken from the same area in early fall 2014 but much closer to shore. Note that the radius of a primary rainbow, about 42 degrees, formed from refraction of sunlight in fresh water (raindrops) is approximately 1 degree larger than the rainbow angle formed in a salty ocean spray.

Photo details: Inset - Camera Model: NIKON D7000; Focal Length: 200mm (35mm equivalent: 300mm); Aperture: ƒ/5.6; Exposure Time: 0.0005 s (1/2000); ISO equiv: 400; Software: Microsoft Windows Live Photo Gallery14.0.8064.206.