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.

    • ‘He also determined the distances, using the heliometer, of twenty of the brighter and nearer Southern stars.’
    • ‘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.’
    • ‘After the expedition the heliometer was donated to the Observatory who built a tower for it.’
    • ‘The heliometer is shown on display at the Science Museum in London.’
    • ‘A heliometer is a refractor, with the objective cut in two, which was used to measure small angular distances.’

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/