celestial navigation


celestial navigation
navigation by means of observations made of the apparent position of heavenly bodies. Also called astronavigation, celo-navigation.
[1935-40]

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      use of the observed positions of celestial bodies to determine a navigator's position. At any moment some celestial body is at the zenith of any particular location on the Earth's surface. This location is called the ground position (GP). GP can thus be stated in terms of celestial coordinates, with the declination of the celestial object equal to latitude and the Greenwich hour angle equal to longitude. Almanacs (almanac) such as those published by the Nautical Almanac Office of the U.S. Naval Observatory provide these coordinates for the Sun, Moon, and planets (or navigator's stars); the tabulations are given in terms of Greenwich Civil Time. From this information a line of position can be plotted. In principle, the line could be drawn on a very large sphere, but, in practice, a Mercator chart, or plotting sheet, is used. The navigator then uses a sextant or bubble octant to measure the altitude of the celestial object and records this altitude using Greenwich Civil Time. The navigator estimates his position, this being the dead-reckoning position. The altitude and the bearing that the celestial object would have at this position are calculated or taken from tables. The dead-reckoning position is marked on the plotting sheet and a line drawn in the direction of the celestial object's calculated bearing. From this information and from the difference between the observed and computed altitudes of the celestial object, known as the intercept, the position of the navigator can be calculated.

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Universalium. 2010.

Look at other dictionaries:

  • Celestial navigation — Celestial navigation, also known as astronavigation, is a position fixing technique that was devised to help sailors cross the featureless oceans without having to rely on dead reckoning to enable them to strike land. Celestial navigation uses… …   Wikipedia

  • celestial navigation — n. navigation based on observation of the sun, moon, stars, or planets to determine position …   English World dictionary

  • celestial navigation — n. astronavigation, navigation of a ship or aircraft according to the position of celestial objects; navigation in space between celestial bodies …   English contemporary dictionary

  • celestial navigation — A form of navigation where the known position of celestial bodies and their angle to the observer, along with the time of the observation, are used to determine position. The exact position of stars is given in a nautical or aeronautical almanac …   Aviation dictionary

  • celestial navigation — Synonyms and related words: VAR, aspect, astronavigation, attitude, automatic electronic navigation, azimuth, bearing, bearings, chronometer, coastwise navigation, consolan, dead reckoning, electronic navigation, exposure, fix, frontage, lay, lie …   Moby Thesaurus

  • celestial navigation — noun Date: 1939 navigation by observation of the positions of celestial bodies …   New Collegiate Dictionary

  • celestial navigation — /səˌlɛstiəl nævəˈgeɪʃən/ (say suh.lesteeuhl navuh gayshuhn) noun navigation based on the positions of celestial bodies. Also, astronavigation …   Australian English dictionary

  • celestial navigation — noun Navigation by using the positions of the stars and other heavenly bodies Syn: astronavigation …   Wiktionary

  • celestial navigation — noun navigation using the sun, moon, and stars …   English new terms dictionary

  • celestial navigation — celes′tial naviga′tion n. naut. navig. navigation by means of observations made of the apparent position of heavenly bodies • Etymology: 1935–40 …   From formal English to slang


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