|Alaska Iridescence captured by Doug Short."These clouds were changing fast and within 10 minutes were overtaken by a solid layer of clouds. The cloud layer showed some iridescence on its leading edge for a few minutes as it merged with the first clouds." ©Doug Short
|Think of iridescence as a fractured and jumbled corona.
Diffraction by a cloud of uniform sized droplets gives multiple coloured rings around the sun - a corona.
When the droplet size varies across a cloud the rings and colours are disordered, changing from place to place - iridescence.