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Belidor, Bernard Forest de

(Encyclopedia)Belidor, Bernard Forest de bĕrnärˈ fôrĕˈ də bālēdôrˈ [key], 1693–1761, French engineer. He wrote numerous books dealing with mathematics, artillery, and hydraulic, civil, and military eng...

ecliptic coordinate system

(Encyclopedia)ecliptic coordinate system, an astronomical coordinate system in which the principal coordinate axis is the ecliptic, the apparent path of the sun through the heavens. The ecliptic poles are the two p...

Chinese examination system

(Encyclopedia)Chinese examination system, civil service recruitment method and educational system employed from the Han dynasty (206 b.c.–a.d. 220) until it was abolished by the Ch'ing dowager empress Tz'u Hsi in...

altazimuth coordinate system

(Encyclopedia)altazimuth coordinate system ăltăzˈəməth [key] or horizon coordinate system, astronomical coordinate system in which the position of a body on the celestial sphere is described relative to an obs...

instrument-landing system

(Encyclopedia)CE5 Instrument-landing system (ILS), the most common instrument-landing approach system, uses two beams to guide an airplane. instrument-landing system (ILS), ground-based radio system designed to...

galactic coordinate system

(Encyclopedia)galactic coordinate system, astronomical coordinate system in which the principal axis is the galactic equator (the intersection of the plane of the Milky Way with the celestial sphere) and the refere...

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