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Astronomical coordinate systems
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The list Astronomical coordinate systems includes
Position angle, Southern celestial hemisphere, Celestial equator, Geocentric model and Declination.
The list consists of 16 members
and 3 sublists.
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1.
Zodiac
twelve signs representing sectors of sky
Overview: The zodiac is a belt-shaped region of the sky that extends approximately 8° north and south celestial latitude of the ecliptic – the apparent path of the Sun across the celestial sphere over the course ...
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Geocentric model
theory that Earth is the centre of the Universe
Overview: In astronomy, the geocentric model (also known as geocentrism, often exemplified specifically by the Ptolemaic system) is a superseded description of the Universe with Earth at the center. Under most ... 0
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Position angle
Convention for measuring angles on the sky
Overview: Position angle, usually abbreviated PA, is the convention for measuring angles on the sky in astronomy. The International Astronomical Union defines it as the angle measured relative to the north celestial ... 0
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Barycenter
Center of mass of multiple bodies orbiting each otherOverview: In astronomy, the barycenter (or barycentre; from the Ancient Greek βαρύς heavy + κέντρον center) is the center of mass of two or more bodies that orbit one another and is the point about which the bodies ... 0
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Southern celestial hemisphere
Southern half of the celestial sphere
Overview: The southern celestial hemisphere, also called the Southern Sky, is the southern half of the celestial sphere; that is, it lies south of the celestial equator. This arbitrary sphere, on which seemingly ... 0
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Celestial equator
Projection of the Earth's equator out into space
Overview: The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth. This plane of reference bases the equatorial coordinate system. In other words, the ... 0
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Right ascension
Astronomical equivalent of longitudeOverview: Right ascension (abbreviated RA; symbol α) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point ... 0
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Declination
astronomical coordinate
Overview: In astronomy, declination (abbreviated dec; symbol δ) is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. The declination ... 0
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9.
Nadir
direction pointing directly below a particular location
Overview: The nadir is the direction pointing directly below a particular location; that is, it is one of two vertical directions at a specified location, orthogonal to a horizontal flat surface. 0
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Zenith
imaginary point directly above a particular location, on the imaginary celestial sphere
Overview: The zenith is the imaginary point on the celestial sphere directly "above" a particular location. "Above" means in the vertical direction (plumb line) opposite to the gravity direction at that location ... 0
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Ecliptic
apparent path of the Sun on the celestial sphere
Overview: The ecliptic or ecliptic plane is the orbital plane of Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology ... 0
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12.
Horizon
apparent line that separates earth from sky
Overview: The horizon is the apparent curve that separates the surface of a celestial body from its sky when viewed from the perspective of an observer on or near the surface of the relevant body. This curve divides ... 0
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Celestial sphere
imaginary sphere of arbitrarily large radius, concentric with the observer
Overview: In astronomy and navigation, the celestial sphere is an abstract sphere that has an arbitrarily large radius and is concentric to Earth. All objects in the sky can be conceived as being projected upon ... 0
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Celestial coordinate system
spherical coordinate systems
Overview: In astronomy, coordinate systems are used for specifying positions of celestial objects (satellites, planets, stars, galaxies, etc.) relative to a given reference frame, based on physical reference points ... 0
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Azimuth
the horizontal angle between north and a point
Overview: An azimuth (from Arabic: اَلسُّمُوت, as-sumūt, 'the directions') is the horizontal angle from a cardinal direction, most commonly north, in a local or observer-centric spherical coordinate system. 0
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Equator
Intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and midway between the poles
Overview: The equator is a circle of latitude that divides a spheroid, such as Earth, into the Northern and Southern hemispheres. On Earth, the equator is an imaginary line located at 0 degrees latitude, about 40,075 ... 0
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