Manage to pursue strange steel instrument (9)
I believe the answer is:
telescope
'instrument' is the definition.
(telescope is a kind of instrument)
'manage to pursue strange steel' is the wordplay.
'manage' becomes 'cope' (manage can mean to cope or do well).
'to pursue' means one lot of letters go next to another.
'strange' indicates an anagram.
'steel' is an anagram of 'teles'.
'cope' put after 'teles' is 'TELESCOPE'.
(Other definitions for telescope that I've seen before include "Glass" , "It magnifies the image of distant objects" , "Instrument to magnify the image of distant objects" , "optical equipment" , "Instrument for viewing distant objects" .)