The blue-green part of the spectrum survives being refracted through
the atmosphere better that longer wavelengths, but occasionally, one
gets the THRILL of seeing nearly a complete rainbow when the sun sets in
crystal-clear conditions!!  I have seen this only once, but it was
incredibly beautiful.  I was hoping only to see the fabled "green
flash", but there appeared instead, a complete, very small rainbow,
which hung there for perhaps 3 seconds.  Has anyone else seen this?
                                                                                                                                                -Ross.