heliometer
/ˌhiːlɪˈɒmɪtə(r)/noun
Astronomy a refracting telescope with a split objective lens, used for finding the angular distance between two stars
【天文】量日仪。
词源
mid 18th cent.: from
HELLO- 'of the sun' +
-METER (because it was originally used for measuring the diameter of the sun).