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  2. List of satellite pass predictors - Wikipedia

    en.wikipedia.org/wiki/List_of_satellite_pass...

    N2YO provides real time tracking and pass predictions with orbital paths and footprints overlaid on Google Maps. [6] It features an alerting system that automatically notifies users via SMS and/or email before International Space Station crosses the local sky. The N2YO.com system powers ESA's, Space.com's and many other's satellite tracking web ...

  3. Sidereal time - Wikipedia

    en.wikipedia.org/wiki/Sidereal_time

    (In the context of sidereal time, "March equinox" or "equinox" or "first point of Aries" is currently a direction, from the center of the Earth along the line formed by the intersection of the Earth's equator and the Earth's orbit around the Sun, toward the constellation Pisces; during ancient times it was toward the constellation Aries.) [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. 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

  6. Hour angle - Wikipedia

    en.wikipedia.org/wiki/Hour_angle

    The local hour angle (LHA) of an object in the observer's sky is = or = + where LHA object is the local hour angle of the object, LST is the local sidereal time, is the object's right ascension, GST is Greenwich sidereal time and is the observer's longitude (positive east from the prime meridian). [3]

  7. Nautical almanac - Wikipedia

    en.wikipedia.org/wiki/Nautical_almanac

    Two sample pages of the 2002 Nautical Almanac published by the U.S. Naval Observatory. A nautical almanac is a publication describing the positions of a selection of celestial bodies for the purpose of enabling navigators to use celestial navigation to determine the position of their ship while at sea.

  8. Astronomical coordinate systems - Wikipedia

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

    Angles in the hours ( h), minutes ( m), and seconds ( s) of time measure must be converted to decimal degrees or radians before calculations are performed. 1 h = 15°; 1 m = 15′; 1 s = 15″ Angles greater than 360° (2 π ) or less than 0° may need to be reduced to the range 0°−360° (0–2 π ) depending upon the particular calculating ...

  9. Zenith - Wikipedia

    en.wikipedia.org/wiki/Zenith

    Zenith stars (also "star on top", "overhead star", "latitude star") [8] are stars whose declination equals the latitude of the observers location, and hence at some time in the day or night pass culminate (pass) through the zenith. When at the zenith the right ascension of the star equals the local sidereal time at your location.