In this way, one can see stars (5)
I believe the answer is:
milky
'in' is the definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I can't see?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for milky that I've seen before include "White, opaque" , "Lacteal; cloudy" , "Of a soft white colour" , "Clouded" , "Lactic" .)