Dark Band Between Rainbows
June 11, 2004
This beautiful double rainbow occurred following a brief rain-shower in the Las Vegas valley around 6:30 p.m. (local time/Mountain Time Zone) on April 8, 2004. The dark band in between the primary and secondary rainbows is known as Alexander's Band. When a secondary rainbow is visible, in addition to the sky being brighter on the inside of the primary bow, it's also brighter to the outside of the secondary bow. Rays of sunlight reflected a second time in raindrops, responsible for forming the secondary bow, also results in a lighter sky above this bow. However, it's not as obvious as the brightening on the inside of the primary rainbow.