It gives us illumination - like a star? (8)
I believe the answer is:
skylight
'it' is the definition.
The definition suggests a singular noun which matches the answer.
'illumination like a star?' is the wordplay.
I cannot quite see how this works, but
'illumination' could be 'light' (synonyms) and 'light' is present in the answer.
'like' could be 'y' (similar in meaning) and 'y' is found within the answer.
This explanation may well be incorrect...
'gives us' acts as a link.
Can you help me to learn more?
(Other definitions for skylight that I've seen before include "Attic window" , "Window in a roof or ceiling" .)