Celestial reference point for navigation (8)
I believe the answer is:
lodestar
'celestial reference point for navigation' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for lodestar that I've seen before include "In navigation, celestial reference point" , "Guiding principle" , "Heavenly guide" , "Travel guide" , "Guiding light; leotards (anag.)" .)