A heavenly high point (6)

I believe the answer is:

zenith

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'high point' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for zenith that I've seen before include "Point in sky directly overhead" , "The highest point directly above" , "Top of battered" , "Meridian" , "The highest point, above in the sky" .)

I've seen this clue in the Evening Standard.

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