heliometer Meaning, Definition & Usage

  1. 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

WordNet

He`li*om"e*ter noun
Etymology
Helio- + -meter: cf. F. héliomètre.
Definitions
  1. (Astron.) An instrument devised originally for measuring the diameter of the sun; now employed for delicate measurements of the distance and relative direction of two stars too far apart to be easily measured in the field of view of an ordinary telescope.

Webster 1913