Definition of astrophotometer in US English:

astrophotometer

noun

Astronomy
historical
  • An instrument for measuring the brightness of a star's light.

Origin

Mid 19th century; earliest use found in American Journal of Science. After German Astrophotometer.

Pronunciation

astrophotometer

/ˌastrə(ʊ)fə(ʊ)ˈtɒmɪtə/