Condensation Trail Iridescence
Jurgen de Boer (site) imaged this aircraft and contrail near to sunset on 2nd May. The aircraft was 10-20° from the sun. The structured iridescence is interesting. Seven or more colour bands are visible. The water droplets or ice crystals of the condensation trail will have had similar formation histories. Perhaps this produced rather uniform sizes and mean size variation along the trail thus accounting for the uniform colour bands?
Posted by Les Cowley