heliometern. 量日化學術名詞量日儀：天文學、物理化學儀器設備、計量學、海事日徑儀：物理化學儀器設備、計量學量日計：物理學太陽儀：測量學英文釋義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