astronomy vs natural philosophy

astronomy and natural philosophy both are nouns.

Word	Noun	Adjective	Verb	Adverb
astronomy	Yes	No	No	No
natural philosophy	Yes	No	No	No

As nouns, natural philosophy is a hypernym of astronomy; that is, natural philosophy is a word with a broader meaning than astronomy:

astronomy: the branch of physics that studies celestial bodies and the universe as a whole
natural philosophy: the science of matter and energy and their interactions

Other hypernyms of astronomy include physics.

astronomy (noun)	natural philosophy (noun)
the branch of physics that studies celestial bodies and the universe as a whole	the science of matter and energy and their interactions