| 单词 | zenith sector |
| 释义 | > as lemmaszenith sector zenith sector n. now historical a type of zenith telescope formerly favoured, having a heavily built mount with fine adjustments for accurate alignment. ΘΚΠ the world > the universe > cosmology > science of observation > astronomical instruments > zenith distance > [noun] zenith sector1775 zenith telescope1803 zenith tube1825 1775 Philos. Trans. (Royal Soc.) 65 499 Which quantities are not too small to be measured and demonstrated by an accurate zenith sector, such as that belonging to the Royal Society. 1829 W. Pearson Pract. Astron. II. 531 The zenith sector..can be used only on the meridian; and its measures are referred to the zenith point of the place of observation. Its principal uses are to determine the latitude of the place of observation by a star of known zenith distance; to measure the zenith distance of a star..; and to ascertain the zenith point. 1970 Notes & Rec. Royal Soc. 24 266 A 5-foot portable zenith sector was found to be difficult both to manipulate and to rectify. 2006 E. Danson Weighing World iv. 33 The expedition was equipped with a 9-foot-tall zenith sector constructed by the London instrument maker George Graham. < as lemmas |
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