Crossword Genius

German dons behind blue atmospheric phenomenon (9)

Ross

I believe the answer is:

afterglow

I'm a little stuck... Click here to teach me more about this clue!

'atmospheric phenomenon' is the definition.
(afterglow is a kind of atmospheric phenomenon)

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for afterglow that I've seen before include "Post-sunset radiance" , "Remaining light" , "appearing when sun has set?" , "residual light" , "Light once the actual source has gone" .)

I've seen this clue in The Independent.
Want a hint initially instead of a full solution? Install my app