Sky viewer may see this tip-top snooker feat, pocketing balls (5,3,4)
I believe the answer is:
great red spot
'sky viewer' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'see this tip-top snooker feat pocketing balls' is the wordplay.
I cannot really understand how this works, but
'see' could be 'spot' (to spot is to notice or catch sight of) and 'spot' is located in the answer.
'top' could be 'great' (both can mean excellent) and 'great' is present in the answer.
'balls' could be 'ed' (I've seen this in other clues) and 'ed' is present in the answer.
A single letter 'r' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'may' is the link.
Can you help me to learn more?
(Other definitions for great red spot that I've seen before include "Visible atmospheric feature on Jupiter" , "Big feature on Jupiter" .)