radio astronomy vs astronomy

radio astronomy and astronomy both are nouns.

Word	Noun	Adjective	Verb	Adverb
radio astronomy	Yes	No	No	No
astronomy	Yes	No	No	No

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

radio astronomy: the branch of astronomy that detects and studies the radio waves emitted by celestial bodies
astronomy: the branch of physics that studies celestial bodies and the universe as a whole

Other hypernyms of radio astronomy include uranology.

radio astronomy (noun)	astronomy (noun)
the branch of astronomy that detects and studies the radio waves emitted by celestial bodies	the branch of physics that studies celestial bodies and the universe as a whole