August 16, 2003
While walking west along Sunset Beach on Oahu, Hawaii, I encountered a brief rain shower about an hour before sunset. After it passed, the Sun came out, and as I turned to see if a rainbow was present, this exquisite bow greeted me -- the biggest rainbow I've ever seen. The secondary second rainbow is also visible (top left). This secondary rainbow is created when the Sun's light is twice reflected in raindrops, and the rays exit the drops at an angle of 51 degrees. For the primary rainbow, the light emerges at an angle of 42 degrees. Note that with the secondary rainbow, the red band is on the inside, the reverse of the primary bow.