Rainbow Airglow over the Azores
A sky glowing like a rainbow can be caused by airglow, often visible during atmospheric disturbances. The colors in the featured image—red from OH molecules and orange/green from sodium and oxygen—are enhanced by a long exposure. Captured in the Azores, the photo also shows the Milky Way and Andromeda Galaxy.
HD image at https://apod.nasa.gov/apod/ap210418.html
