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The items include two sextants, an octant, and a telescope. [3] American Arctic explorer Charles Francis Hall (1821–1871) owned one of the sextants. It is believed that this brass sextant was most probably with him on 30 August 1871. [19] On that day, Hall (pictured) had arrived at the furthest northern point achieved by an explorer to date.
The frame of a sextant is in the shape of a sector which is approximately 1 ⁄ 6 of a circle (60°), [3] hence its name (sextāns, sextantis is the Latin word for "one sixth"). "). Both smaller and larger instruments are (or were) in use: the octant, quintant (or pentant) and the (doubly reflecting) quadrant [4] span sectors of approximately 1 ⁄ 8 of a circle (45°), 1 ⁄ 5 of a circle (72 ...
The Bris sextant / ˈ b r iː s /, or Bris Mini-Sextant, is not a sextant proper, but is a small angle-measuring device that can be used for navigation. [ 1 ] [ 2 ] The Bris is, however, a true reflecting instrument which derives its high accuracy from the same principle of double reflection which is fundamental to the octant, the true sextant ...
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A stadimeter operator adjusts the lower knob until the top and bottom of the object are aligned, and then reads the corresponding range off the edge of the lower knob through a small magnifying lens. A stadimeter is an optical device for estimating the range to an object of known height by measuring the angle between the top and bottom of the ...
A diagram of a typical nautical sextant, a tool used in celestial navigation to measure the angle between two objects viewed by means of its optical sight. Celestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space or on the ...
In astronavigation, sight reduction is the process of deriving from a sight (in celestial navigation usually obtained using a sextant) the information needed for establishing a line of position, generally by intercept method.
From that time onward, the sextant was the instrument that experienced significant development and improvements and was the instrument of choice for naval navigators. The octant continued to be produced well into the 19th century, though it was generally a less accurate and less expensive instrument.