Reflection Rainbow Over Swan Bay, Victoria

November 13, 2011

Relectionbow6 13 11- 16_resize (2)

Photographer: Phil Thomson; Phil's Web site
Summary Author: Phil Thomson; Jim Foster

November 2011 Earth Science Picture of the Day Viewer's ChoiceHow many of you have ever seen a rainbow like the one above? The presence of water nearby is the key to having a chance to observe such a bow. This picture was snapped in Swan Bay, just off the Bellarine Peninsula of Victoria, Australia. It's not a double rainbow, which consists of primary and secondary rainbows, but rather a reflection rainbow that magically appeared preceding a rain shower that swept in from Queenscliff. Reflection bows occur when sunlight reflects off a smooth body of water, into the sky, at a higher angle than the light responsible for causing the primary bow (approximately 42 degrees). In essence, the reflection of sunlight from the bay waters interacted with the raindrops to form another rainbow -- the one to the left. 

It's usually possible to tell if a bow is reflected or not since the color sequence is the same as that of the primary bow. The sequence is reversed with a secondary bow (upper left). Because the Sun was so low when this photo was captured, the red colors dominate; nonetheless, a lighter blue band can be seen on the inside of both the primary and reflection rainbows. A low Sun is almost essential for viewing a reflection bow since high-in-the-sky Suns don't reflect sunlight as strongly. Photo taken on June 13, 2011.

Photo details: Camera Maker: PENTAX; Camera Model: PENTAX K-5; Focal Length: 35mm (35mm equivalent: 52mm); Aperture: f/14.0; Exposure Time: 0.400 s (1/3); ISO equiv: 80; Exposure Bias: -0.30 EV;
Metering Mode: Matrix; Exposure: Manual; Exposure Mode: Manual; White Balance: Manual; Flash Fired: No (enforced); Orientation: Normal; Software: ACD Systems Digital Imaging.