Back نظام الإحداثيات الاستوائية Arabic Coordenaes ecuatoriales AST Экватарыяльная сістэма каардынат Byelorussian Екваториална координатна система Bulgarian Coordenades equatorials Catalan Rovníkové souřadnice Czech Äquatoriales Koordinatensystem German Ekvatora koordinatsistemo Esperanto Coordenadas ecuatoriales Spanish Ekvaatorilised koordinaadid Estonian
The equatorial coordinate system is a celestial coordinate system widely used to specify the positions of celestial objects. It may be implemented in spherical or rectangular coordinates, both defined by an origin at the centre of Earth, a fundamental plane consisting of the projection of Earth's equator onto the celestial sphere (forming the celestial equator), a primary direction towards the March equinox, and a right-handed convention.[1][2]
The origin at the centre of Earth means the coordinates are geocentric, that is, as seen from the centre of Earth as if it were transparent.[3] The fundamental plane and the primary direction mean that the coordinate system, while aligned with Earth's equator and pole, does not rotate with the Earth, but remains relatively fixed against the background stars. A right-handed convention means that coordinates increase northward from and eastward around the fundamental plane.
- ^ Nautical Almanac Office, U.S. Naval Observatory; H.M. Nautical Almanac Office; Royal Greenwich Observatory (1961). Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac. H.M. Stationery Office, London (reprint 1974). pp. 24, 26.
- ^ Vallado, David A. (2001). Fundamentals of Astrodynamics and Applications. Microcosm Press, El Segundo, CA. p. 157. ISBN 1-881883-12-4.
- ^ U.S. Naval Observatory Nautical Almanac Office; U.K. Hydrographic Office; H.M. Nautical Almanac Office (2008). The Astronomical Almanac for the Year 2010. U.S. Govt. Printing Office. p. M2, "apparent place". ISBN 978-0-7077-4082-9.