Something heavenly not in full view (3,4)
I believe the answer is:
new moon
'view' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for new moon that I've seen before include "Heavenly body, just visible" , "emergent body" , "heavenly vision" , "First phase(s) of lunar cycle" , "First appearance of a waxing satellite" .)