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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. Four corners of the world - Wikipedia

    en.wikipedia.org/wiki/Four_corners_of_the_world

    In Mesopotamian cosmology, four rivers flowing out of the garden of creation, which is the center of the world, define the four corners of the world. [1] From the point of view of the Akkadians, the northern geographical horizon was marked by Subartu, the west by Mar.tu, the east by Elam and the south by Sumer; later rulers of all of Mesopotamia, such as Cyrus, claimed among their titles LUGAL ...

  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. Astronomical coordinate systems - Wikipedia

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

    The fundamental plane is the plane of the Earth's orbit, called the ecliptic plane. There are two principal variants of the ecliptic coordinate system: geocentric ecliptic coordinates centered on the Earth and heliocentric ecliptic coordinates centered on the center of mass of the Solar System.

  6. Solar azimuth angle - Wikipedia

    en.wikipedia.org/wiki/Solar_azimuth_angle

    The solar azimuth angle is the azimuth (horizontal angle with respect to north) of the Sun's position. [1] [2] [3] This horizontal coordinate defines the Sun's relative direction along the local horizon, whereas the solar zenith angle (or its complementary angle solar elevation) defines the Sun's apparent altitude.

  7. Geographical centre of Earth - Wikipedia

    en.wikipedia.org/wiki/Geographical_centre_of_Earth

    Geometrically defined it is the centroid of all land surfaces within the two dimensions of the Geoid surface which approximates the Earth's outer shape. The term centre of minimum distance [ 1 ] specifies the concept more precisely as the domain is the sphere surface without boundary and not the three-dimensional body.

  8. 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

  9. Hemispheres of Earth - Wikipedia

    en.wikipedia.org/wiki/Hemispheres_of_Earth

    This hemisphere contains approximately 68% of Earth's landmass and is home to about 90% of the global population. [4] It includes North America, Europe, Asia, and most of Africa. Southern Hemisphere: The half that lies south of the Equator. It contains approximately 32% of Earth's landmass and is home to about 10% of the global population.