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Two sample pages of the 2002 Nautical Almanac. The Nautical Almanac has been the familiar name for a series of official British almanacs published under various titles since the first issue of The Nautical Almanac and Astronomical Ephemeris, for 1767: [1] this was the first nautical almanac to contain data dedicated to the convenient determination of longitude at sea.
Two sample pages of the 2002 Nautical Almanac published by the U.S. Naval Observatory. A nautical almanac is a publication describing the positions of a selection of celestial bodies for the purpose of enabling navigators to use celestial navigation to determine the position of their ship while at sea.
In astronomy and celestial navigation, an ephemeris (/ ɪ ˈ f ɛ m ər ɪ s /; pl. ephemerides / ˌ ɛ f ə ˈ m ɛr ɪ ˌ d iː z /; from Latin ephemeris 'diary', from Ancient Greek ἐφημερίς (ephēmerís) 'diary, journal') [1] [2] [3] is a book with tables that gives the trajectory of naturally occurring astronomical objects and artificial satellites in the sky, i.e., the position ...
Air Almanac [11]; Astronomical Almanac; Astronomical Phenomena [12]; The Astronomical Pocket Diary (1987–present); Multiyear Interactive Computer Almanac [13]; The Nautical Almanac (1767–present under various titles; prepared by U.S. Naval Observatory and Her Majesty's Nautical Almanac Office since 1958)
The American Ephemeris and Nautical Almanac was published for the years 1855 to 1980, containing information necessary for astronomers, surveyors, and navigators. It was based on the original British publication, The Nautical Almanac and Astronomical Ephemeris, with which it merged to form The Astronomical Almanac, published from the year 1981 to the present.
JPL Horizons On-Line Ephemeris System provides access to key Solar System data and flexible production of highly accurate ephemerides for Solar System objects. Osculating elements at a given epoch (such as produced by the JPL Small-Body Database ) are always an approximation to an object's orbit (i.e. an unperturbed conic orbit or a " two-body ...
What remains is the set of data needed to update the original G-card data as additional measurements are made. The data is fit into 69 columns and does not include a trailing character. TLEs are simply the transmission format data rendered as ASCII text. An example TLE for the International Space Station:
The receiver has estimates of the current time within 20 seconds, the current position within 100 kilometers, its velocity within 25 m/s, and it has valid almanac data. It must acquire each satellite signal and obtain that satellite's detailed orbital information, called ephemeris data. Each satellite broadcasts its ephemeris data every 30 ...