Clock catalogue (8)
I believe the answer is:
register
I believe this clue is a double definition.
'clock' is the first definition.
(both can mean to observe or comprehend something)
'catalogue' is the second definition.
(I've seen this before)
(Other definitions for register that I've seen before include "Official list or record" , "New arrival at hotel will" , "Annals" , "Make an impression: sign on" , "To express" .)