An aspect unaffected by the stars (8)
I believe the answer is:
sidereal
'an aspect unaffected by the stars' is the definition.
I can't judge whether this definition defines the answer.
'an aspect unaffected by' is the wordplay.
'an aspect' becomes 'side' (side is a kind of aspect).
'unaffected' becomes 'real' (I've seen this before).
'by' is a charade indicator (letters next to each other).
'side'+'real'='SIDEREAL'
Can you help me to learn more?
(Other definitions for sidereal that I've seen before include "Of the stars or constellations" , "Like stars" , "Relating to the constellations" , "Of or measured by the stars" , "Realised (anag) -- relating to the stars" .)