Definition of heliometer in English:

heliometer

noun

Astronomy
  • A refracting telescope with a split objective lens, used for finding the angular distance between two stars.

    • ‘A heliometer is a refractor, with the objective cut in two, which was used to measure small angular distances.’
    • ‘The heliometer is shown on display at the Science Museum in London.’
    • ‘He also determined the distances, using the heliometer, of twenty of the brighter and nearer Southern stars.’
    • ‘After the expedition the heliometer was donated to the Observatory who built a tower for it.’
    • ‘And so, the phenomenon in 1882 was observed by cameras held by the French and the Americans, and timings were measured with the help of heliometers in most European organizations.’

Origin

Mid 18th century: from helio- ‘of the sun’ + -meter (because it was originally used for measuring the diameter of the sun).

Pronunciation

heliometer

/ˌhiːlɪˈɒmɪtə/