apex vs celestial point

apex and celestial point both are nouns.

Word	Noun	Adjective	Verb	Adverb
apex	Yes	No	No	No
celestial point	Yes	No	No	No

As nouns, celestial point is a hypernym of apex; that is, celestial point is a word with a broader meaning than apex:

apex: the point on the celestial sphere toward which the sun and solar system appear to be moving relative to the fixed stars
celestial point: a point in the heavens (on the celestial sphere)

apex (noun)	celestial point (noun)
the highest point (of something)	a point in the heavens (on the celestial sphere)
the point on the celestial sphere toward which the sun and solar system appear to be moving relative to the fixed stars