Parrot biting hard — cat finds point in orbit (8)
I believe the answer is:
aphelion
'in orbit' is the definition.
('aphelion' is part of 'orbit')
'parrot biting hard cat' is the wordplay.
'parrot' becomes 'ape' (both can mean to imitate).
'biting' means one lot of letters goes inside another (some letters bite or swallow others).
'hard' becomes 'h' (abbreviation used in pencil classifications).
'cat' becomes 'lion' (lion is a kind of cat).
'ape' going around 'h' is 'aphe'.
'aphe'+'lion'='APHELION'
'finds point' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for aphelion that I've seen before include "maximum distance from sun" , "Point well away from star" , "Point in planet's orbit" .)