Late Saturday afternoon 9/29/2012, I was at my favorite coffee shop when, Lo and Behold, a most glorious sight appeared.
When you see a primary rainbow, you are seeing light that has been refracted and
reflected through water droplets, however the red color does not come
from exactly the same droplets of water as the violet color. If you
were able to isolate one particular water drop that produced some of the
red color you saw, the violet light from this drop would not meet your
eyes - it would travel over your head.
A secondary rainbow is produced when there is one extra reflection of
light within the water drop. As some light is lost each time it hits the
edge of the drop, the secondary rainbow is fainter than the first. It
appears higher in the sky because the light exits the drop at a larger
angle (50-53 degrees) than the primary rainbow (40-42 degrees).