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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 ...
The number used to identify stars in navigation publications and star charts. [Note 2] Common name The name of the star commonly used navigation publications and star charts. Bayer designation: Another name of the star which combines a Greek letter with the possessive form of its constellation's Latin name. Etymology of common name
In the mid-1st century AD Lucan writes of Pompey who questions a sailor about the use of stars in navigation. The sailor replies with his description of the use of circumpolar stars to navigate by. [10] To navigate along a degree of latitude a sailor would have needed to find a circumpolar star above that degree in the sky. [11]
The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle, the altitude, is known as sighting or shooting the object, or taking a sight .
Marine chronometer used to determine time at the prime meridian with great precision which is necessary when reducing sights in celestial navigation. Nocturnal used to determine apparent local time by viewing the Polaris and its surrounding stars. Ring dial or astronomical ring used to measure the height of a celestial body above the horizon ...
The positions of the stars helped guide Polynesian voyages. Stars, as opposed to planets, hold fixed celestial positions year-round, changing only their rising time with the seasons. Each star has a specific declination, and can give a bearing for navigation as it rises or sets. Polynesian voyagers would set a heading by a star near the horizon ...
The "Air Almanac" of the United States and Great Britain tabulates celestial coordinates for 10-minute intervals for use in aerial navigation. The Sokkia Corporation's annual "Celestial Observation Handbook and Ephemeris" tabulated daily celestial coordinates (to a tenth of an arcsecond) for the Sun and nine stars; it was last published for 2008.
Longitude by chronometer is a method, in navigation, of determining longitude using a marine chronometer, which was developed by John Harrison during the first half of the eighteenth century. It is an astronomical method of calculating the longitude at which a position line, drawn from a sight by sextant of any celestial body, crosses the ...