Celestial air navigation1/13/2024 ![]() In addition to tables, star charts provide an aid to the navigator in identifying the navigational stars, showing constellations, relative positions, and brightness. A second group of 115 "tabulated stars" can also be used for celestial navigation, but are often less familiar to the navigator and require extra calculations.Īlthough Polaris can quickly and simply give a solution for latitude in the northern hemisphere, it can not participate in giving a position fix including longitude - it is for this reason it is excluded from the list of 57 primary navigational stars, each of which can be used to produce (in conjunction with each other, known time in relation to the prime meridian and a set of sight reduction tables) an actual latitudinal and longitudinal positional fix.įor purposes of identification, the positions of navigational stars - expressed as declination and sidereal hour angle - are often rounded to the nearest degree. ![]() The other 57 selected stars have daily positions given in nautical almanacs, aiding the navigator in efficiently performing observations on them. When navigating in the Northern Hemisphere, a simple and quick technique can be used with Polaris to determine the observers latitude or, for larger maritime vessels can be used to calculate any gyrocompass error that may exist. The star Polaris, often called either the "Pole Star" or the "North Star", is treated specially due to its proximity to the north celestial pole. Many of the selected stars were named in antiquity by the Babylonians, Greeks, Romans, and Arabs. Of the approximately 6,000 stars visible to the naked eye under optimal conditions, these selected stars are among the brightest and span 38 constellations of the celestial sphere from the declination of −70° to +89°. ![]() The selected stars for navigation are often used for sextant observations.įifty-seven navigational stars and additionally the star Polaris are given a special status in the field of celestial navigation.
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