iridescence

Optical phenomenon consisting of a set of colors that appear in high and mid-level clouds located a short angular distance from the sun. It is due, in most cases, to the diffraction of light. It can appear with the colors intermingled or forming bands almost parallel to the cloud contours, in which pastel green and pink colors predominate. The proximity of the solar disk (the light source) to the clouds with iridescence makes it difficult to observe. Wearing polarized sunglasses makes it possible to appreciate it clearly.