Judge performer to have ruined first telescope (9)

I believe the answer is:

refractor

'telescope' is the definition.
(thesaurus)

'judge performer to have ruined first' is the wordplay.
'judge' becomes 'ref' (referee).
'performer' becomes 'actor' (actor is a kind of performer).
'to have' indicates putting letters inside.
'ruined first' becomes 'r' (ast letter of 'ruined').
'ref'+'actor'='refactor'
'refactor' going around 'r' is 'REFRACTOR'.

I've seen this clue in The Daily Express.

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