Bobby viewed in telescope (3)
I believe the answer is:
cop
'bobby' is the definition.
(I've seen this in other clues)
'viewed in telescope' is the wordplay.
'viewed in' indicates the answer is hidden within the clue.
'COP' is hidden within 'telescope'.
(Other definitions for cop that I've seen before include "Policeman (informal)" , "Policeman (colloq.)" , "Policeman (sl)" , "Get" , "Police officer (informal)" .)