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  2. Solar coordinate systems - Wikipedia

    en.wikipedia.org/wiki/Solar_coordinate_systems

    The Carrington heliographic coordinate system, established by Richard C. Carrington in 1863, rotates with the Sun at a fixed rate based on the observed rotation of low-latitude sunspots. It rotates with a sidereal period of exactly 25.38 days, which corresponds to a mean synodic period of 27.2753 days.

  3. Astronomical coordinate systems - Wikipedia

    en.wikipedia.org/wiki/Astronomical_coordinate...

    Coordinate system [2] Center point (origin) Fundamental plane (0° latitude) Poles Coordinates Primary direction (0° longitude) Latitude Longitude Horizontal (also called alt-az or el-az) Observer Horizon: Zenith, nadir: Altitude (a) or elevation Azimuth (A) North or south point of horizon Equatorial: Center of the Earth (geocentric), or Sun ...

  4. Solar longitude - Wikipedia

    en.wikipedia.org/wiki/Solar_longitude

    Solar longitude, commonly abbreviated as Ls, is the ecliptic longitude of the Sun, i.e. the position of the Sun on the celestial sphere along the ecliptic.It is also an effective measure of the position of the Earth (or any other Sun-orbiting body) in its orbit around the Sun, [1] usually taken as zero at the moment of the vernal equinox. [2]

  5. Ecliptic coordinate system - Wikipedia

    en.wikipedia.org/wiki/Ecliptic_coordinate_system

    The system's origin can be the center of either the Sun or Earth, its primary direction is towards the March equinox, and it has a right-hand convention. It may be implemented in spherical or rectangular coordinates. [2] Earth-centered ecliptic coordinates as seen from outside the celestial sphere.

  6. Position of the Sun - Wikipedia

    en.wikipedia.org/wiki/Position_of_the_Sun

    The time when the Sun transits the observer's meridian depends on the geographic longitude. To find the Sun's position for a given location at a given time, one may therefore proceed in three steps as follows: [1] [2] calculate the Sun's position in the ecliptic coordinate system, convert to the equatorial coordinate system, and

  7. Origin (mathematics) - Wikipedia

    en.wikipedia.org/wiki/Origin_(mathematics)

    The origin of a Cartesian coordinate system. In mathematics, the origin of a Euclidean space is a special point, usually denoted by the letter O, used as a fixed point of reference for the geometry of the surrounding space. In physical problems, the choice of origin is often arbitrary, meaning any choice of origin will ultimately give the same ...

  8. Cartesian coordinate system - Wikipedia

    en.wikipedia.org/wiki/Cartesian_coordinate_system

    A Cartesian coordinate system in two dimensions (also called a rectangular coordinate system or an orthogonal coordinate system [8]) is defined by an ordered pair of perpendicular lines (axes), a single unit of length for both axes, and an orientation for each axis. The point where the axes meet is taken as the origin for both, thus turning ...

  9. Sun - Wikipedia

    en.wikipedia.org/wiki/Sun

    The Sun is 1.4 million kilometers (4.643 light-seconds) wide, about 109 times wider than Earth, or four times the Lunar distance, and contains 99.86% of all Solar System mass. The Sun is a G-type main-sequence star that makes up about 99.86% of the mass of the Solar System. [26]