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  2. Planetarium software - Wikipedia

    en.wikipedia.org/wiki/Planetarium_software

    Planetarium software is application software that allows a user to simulate the celestial sphere at any time of day, especially at night, on a computer.Such applications can be as rudimentary as displaying a star chart or sky map for a specific time and location, or as complex as rendering photorealistic views of the sky.

  3. Astronomical clock - Wikipedia

    en.wikipedia.org/wiki/Astronomical_clock

    It has a concentric dial showing the 24-hour time, the date and zodiac, and the moon phase, and a star map dial with a dragon hand, and indicates the time of sunrise and sunset. [19] Třebíč. At the Třebíč Astronomical Observatory, a modern astronomical clock which shows the time in world cities, the time of sunrise and sunset, the date ...

  4. Star chart - Wikipedia

    en.wikipedia.org/wiki/Star_chart

    A celestial map by the Dutch cartographer Frederik de Wit, 1670. A star chart is a celestial map of the night sky with astronomical objects laid out on a grid system. They are used to identify and locate constellations, stars, nebulae, galaxies, and planets. [1] They have been used for human navigation since time immemorial. [2]

  5. Longitude by chronometer - Wikipedia

    en.wikipedia.org/wiki/Longitude_by_chronometer

    Time sight is a general method for determining longitude by celestial observations using a chronometer; these observations are reduced by solving the navigational triangle for meridian angle and require known values for altitude, latitude, and declination; the meridian angle is converted to local hour angle and compared with Greenwich hour angle.

  6. Sidereal time - Wikipedia

    en.wikipedia.org/wiki/Sidereal_time

    Sidereal time ("sidereal" pronounced / s aɪ ˈ d ɪər i əl, s ə-/ sy-DEER-ee-əl, sə-) is a system of timekeeping used especially by astronomers. Using sidereal time and the celestial coordinate system, it is easy to locate the positions of celestial objects in the night sky.

  7. Hour circle - Wikipedia

    en.wikipedia.org/wiki/Hour_circle

    A meridian on the celestial sphere matches an hour circle at any time. The hour circle is a subtype whereby it is expressed in hours as opposed to degrees, radians , or other units of angle. The hour circles make for easy prediction of the angle (and time due to Earth's fairly regular rotation , approximately equal to the time) between the ...

  8. Spacetime diagram - Wikipedia

    en.wikipedia.org/wiki/Spacetime_diagram

    A spacetime diagram is a graphical illustration of locations in space at various times, especially in the special theory of relativity.Spacetime diagrams can show the geometry underlying phenomena like time dilation and length contraction without mathematical equations.

  9. Hour angle - Wikipedia

    en.wikipedia.org/wiki/Hour_angle

    In astronomy and celestial navigation, the hour angle is the dihedral angle between the meridian plane (containing Earth's axis and the zenith) and the hour circle (containing Earth's axis and a given point of interest). [1] It may be given in degrees, time, or rotations depending on the application.