Italian astronomer (7)
I believe the answer is:
galileo
'italian astronomer' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for galileo that I've seen before include "Pioneer scientist" , "Italian astronomer who had trouble with church" , "It. C 16 to 17 astronomer" , "Great Italian astronomer, a founder of modern science" , "Refracting telescope inventor" .)