As used for recording great times on the river? (7)
I believe the answer is:
cameras
'as used for recording great' is the definition.
I can't judge whether this definition defines the answer.
'times on the river?' is the wordplay.
'times' becomes 'eras' (era is a kind of time).
'on' says to put letters next to each other.
'the river?' becomes 'cam' (river in Cambridge, England).
'eras' after 'cam' is 'CAMERAS'.
Can you help me to learn more?
(Other definitions for cameras that I've seen before include "television equipment" , "Image recorders" , "Light-proof boxes" .)