heliometer vs measuring device

heliometer and measuring device both are nouns.

Word	Noun	Adjective	Verb	Adverb
heliometer	Yes	No	No	No
measuring device	Yes	No	No	No

As nouns, measuring device is a hypernym of heliometer; that is, measuring device is a word with a broader meaning than heliometer:

heliometer: an instrument used to measure the angular separation of two stars that are too far apart to be included in the field of view of an ordinary telescope
measuring device: instrument that shows the extent or amount or quantity or degree of something

Other hypernyms of heliometer include measuring instrument, measuring system.

heliometer (noun)	measuring device (noun)
an instrument used to measure the angular separation of two stars that are too far apart to be included in the field of view of an ordinary telescope	instrument that shows the extent or amount or quantity or degree of something