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  2. 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 ...

  3. Star chart - Wikipedia

    en.wikipedia.org/wiki/Star_chart

    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]

  4. Celestial navigation - Wikipedia

    en.wikipedia.org/wiki/Celestial_navigation

    A diagram of a typical nautical sextant, a tool used in celestial navigation to measure the angle between two objects viewed by means of its optical sight. Celestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space or on the ...

  5. Sidereal time - Wikipedia

    en.wikipedia.org/wiki/Sidereal_time

    Animation showing the difference between a sidereal day and a solar day. Sidereal time ("sidereal" pronounced / saɪˈdɪəriəl, sə -/ 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.

  6. Orbital period - Wikipedia

    en.wikipedia.org/wiki/Orbital_period

    Orbit insertion. v. t. e. The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars.

  7. List of stars for navigation - Wikipedia

    en.wikipedia.org/wiki/List_of_stars_for_navigation

    The other two cover the equatorial region of the celestial sphere, from the declination of 30° south to 30° north. The two equatorial charts are mercator projections, one for the eastern hemisphere of the celestial sphere and one for the western hemisphere. Note that unlike familiar maps, east is shown to the left and west is shown to the right.

  8. Sextant - Wikipedia

    en.wikipedia.org/wiki/Sextant

    Sextant. A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle, the altitude, is known as sighting or shooting ...

  9. Epoch (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Epoch_(astronomy)

    Epoch (astronomy) In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to perturbations and vary with time. [1] These time-varying astronomical quantities might ...