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  2. Angular distance - Wikipedia

    en.wikipedia.org/wiki/Angular_distance

    Angular distance appears in mathematics (in particular geometry and trigonometry) and all natural sciences (e.g., kinematics, astronomy, and geophysics). In the classical mechanics of rotating objects, it appears alongside angular velocity, angular acceleration, angular momentum, moment of inertia and torque.

  3. Rayleigh sky model - Wikipedia

    en.wikipedia.org/wiki/Rayleigh_sky_model

    Hence the distance is greatest when looking directly away from the Sun along the horizon in the east, and lowest along the horizon in the west. The bottom plot in the figure to the left represents the angular distance from the observed pointing to the zenith, which is opposite to the interior angle located at the Sun.

  4. Horizontal coordinate system - Wikipedia

    en.wikipedia.org/wiki/Horizontal_coordinate_system

    Azimuth is measured eastward from the north point (sometimes from the south point) of the horizon; altitude is the angle above the horizon. The horizontal coordinate system is a celestial coordinate system that uses the observer's local horizon as the fundamental plane to define two angles of a spherical coordinate system: altitude and azimuth.

  5. Sextant - Wikipedia

    en.wikipedia.org/wiki/Sextant

    The frame of a sextant is in the shape of a sector which is approximately 1 ⁄ 6 of a circle (60°), [2] hence its name (sextāns, sextantis is the Latin word for "one sixth"). "). Both smaller and larger instruments are (or were) in use: the octant, quintant (or pentant) and the (doubly reflecting) quadrant [3] span sectors of approximately 1 ⁄ 8 of a circle (45°), 1 ⁄ 5 of a circle (72 ...

  6. Celestial navigation - Wikipedia

    en.wikipedia.org/wiki/Celestial_navigation

    In the adjacent image, the two circles on the map represent lines of position for the Sun and Moon at 12:00 GMT on October 29, 2005. At this time, a navigator on a ship at sea measured the Moon to be 56° above the horizon using a sextant. Ten minutes later, the Sun was observed to be 40° above the horizon.

  7. Meridian altitude - Wikipedia

    en.wikipedia.org/wiki/Meridian_altitude

    By subtracting this from 90°, he would find that the zenith distance is 90°, which is his latitude. Observer C at the same time is at latitude 20°N on the same meridian, i.e. on the same longitude as Observer A. His measured altitude would be 70°, and subtracting this from 90° gives a 20° zenith distance, which in turn is his latitude. In ...

  8. Spherical coordinate system - Wikipedia

    en.wikipedia.org/wiki/Spherical_coordinate_system

    Instead of the radial distance r geographers commonly use altitude above or below some local reference surface (vertical datum), which, for example, may be the mean sea level. When needed, the radial distance can be computed from the altitude by adding the radius of Earth , which is approximately 6,360 ± 11 km (3,952 ± 7 miles).

  9. Solar zenith angle - Wikipedia

    en.wikipedia.org/wiki/Solar_zenith_angle

    The solar zenith angle is the zenith angle of the sun, i.e., the angle between the sun’s rays and the vertical direction.It is the complement to the solar altitude or solar elevation, which is the altitude angle or elevation angle between the sun’s rays and a horizontal plane.