Sextant
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A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. Its primary use is to measure the angle between an astronomical object and the ho
A sextant
Sextants can also be used by navigators to measure horizontal angles between objects.
Backstaff
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The backstaff is a navigational instrument that was used to measure the altitude of a celestial body, in particular the Sun or Moon. When observing the Sun, users kept the Sun to their back and observ
Sextant
…In 1922, Portuguese navigator and naval officer Carlos Viegas Gago Coutinho modified the sextant for aeronautical navigation. Like the Davis quadrant, the sextant allows celestial objects to be measured relative to the horizon, rather than relative to the instrument. This allows excellent precision…
Davis quadrant, made in 1765 by Johannes Van Keulen. On display at the Musée national de la Marine in Paris.