Illumination from the earth's satellite (9)
I believe the answer is:
moonlight
'illumination from the earth's satellite' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for moonlight that I've seen before include "Night-time illumination" , "Natural (and romantic?) illumination" , "Work in a secondary job" , "Hold a second job" , "Beethoven composition for piano" .)