Backstaff Back"staff`, n. An instrument formerly used for taking the altitude of the heavenly bodies, but now superseded by the quadrant and sextant; -- so called because the observer turned his back to the body observed. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

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  • Backstaff — Not to be confused with Ballastella. Davis quadrant from the beginning of the 18th century The backstaff or back quadrant is a navigational instrument that was used to measure the altitude of a celestial body, in particular the sun or moon. When… …   Wikipedia

  • backstaff — noun An early navigational instrument for measuring the altitude of the sun and hence calculating latitude …   Wiktionary

  • backstaff — ˈ ̷ ̷ˌ ̷ ̷ noun Etymology: back (I) + staff; from the position of the observer, who has his back to the sun when using it : an instrument similar to a cross staff but fitted with a reflector and formerly used for taking the altitudes of heavenly… …   Useful english dictionary

  • Jacob's staff — with four transom For the plant known as the ocotillo, sometimes called the Jacob s staff, see ocotillo. The Jacob s staff, also called a cross staff, a ballastella, a fore staff, or a balestilha is used to refer to several things. This can lead… …   Wikipedia

  • Sextant — This article is about the sextant as used for navigation. For the astronomer s sextant, see Sextant (astronomical). : For the history and development of the sextant see Reflecting instruments A sextant is an instrument generally used to measure… …   Wikipedia

  • Elton's quadrant — An Elton s quadrant is a derivative of the Davis quadrant. It adds an index arm and artificial horizon to the instrument. It was invented by John Elton a sea captain who patentedhis design in 1728Bennett, Jim, Catadioptrics and commerce in… …   Wikipedia

  • Sextante — Para el software SEXTANTE, véase SEXTANTE (SIG). Para el sextante de uso astronómico, véase sextante astronómico. Un sextante. El sextante es un instrumento que permite medir ángulos entre dos objetos tales como dos puntos de una costa o un astro …   Wikipedia Español

  • John Davis (English explorer) — Infobox Person name = John Davis image size = 200 px caption = 17th century painting of Davis birth name = birth date = 1550? birth place = Sandridge, Devon, England death date = death date|1605|12|29 death place = Bintan, Sumatra body discovered …   Wikipedia

  • James Cook — This article is about the British explorer. For other uses, see James Cook (disambiguation). Captain Cook redirects here. For other uses, see Captain Cook (disambiguation). James Cook …   Wikipedia

  • Sundial — A sundial is a device that measures time by the position of the Sun. In common designs such as the horizontal sundial, the sun casts a shadow from its style (a thin rod or a sharp, straight edge) onto a flat surface marked with lines indicating… …   Wikipedia

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