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  2. Lunar distance (navigation) - Wikipedia

    en.wikipedia.org/wiki/Lunar_distance_(navigation)

    In celestial navigation, lunar distance, also called a lunar, is the angular distance between the Moon and another celestial body. The lunar distances method uses this angle and a nautical almanac to calculate Greenwich time if so desired, or by extension any other time. That calculated time can be used in solving a spherical triangle.

  3. Lunar distance - Wikipedia

    en.wikipedia.org/wiki/Lunar_distance

    In contrast, the Lunar distance (LD or ), or Earth–Moon characteristic distance, is a unit of measure in astronomy. More technically, it is the semi-major axis of the geocentric lunar orbit . The lunar distance is on average approximately 385,000 km (239,000 mi), or 1.28 light-seconds ; this is roughly 30 times Earth's diameter or 9.5 times ...

  4. Lunar Laser Ranging experiments - Wikipedia

    en.wikipedia.org/wiki/Lunar_Laser_Ranging...

    Lunar Laser Ranging (LLR) is the practice of measuring the distance between the surfaces of the Earth and the Moon using laser ranging. The distance can be calculated from the round-trip time of laser light pulses travelling at the speed of light , which are reflected back to Earth by the Moon's surface or by one of several retroreflectors ...

  5. On the Sizes and Distances (Aristarchus) - Wikipedia

    en.wikipedia.org/wiki/On_the_Sizes_and_Distances...

    Distance from the Earth to the Moon: S: Distance from the Earth to the Sun: ℓ: Radius of the Moon: s: Radius of the Sun: t: Radius of the Earth: D: Distance from the center of Earth to the vertex of Earth's shadow cone d: Radius of the Earth's shadow at the location of the Moon n: Ratio, d/ℓ (a directly observable quantity during a lunar ...

  6. 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 ...

  7. Astronomical unit - Wikipedia

    en.wikipedia.org/wiki/Astronomical_unit

    Lunar distance: 0.0026 — Average distance from Earth (which the Apollo missions took about 3 days to travel) — Solar radius: 0.005 — Radius of the Sun (695 500 km, 432 450 mi, a hundred times the radius of Earth or ten times the average radius of Jupiter) — Light-minute: 0.12 — Distance light travels in one minute — Mercury: 0.39 —

  8. Nasa issues alert for stadium-sized asteroid approaching Earth

    www.aol.com/nasa-issues-alert-stadium-sized...

    Reaching a minimum distance that is 2.6 times the average lunar distance, 2024 ON poses no risk to Earth on its current trajectory, however even a small deviation could have major consequences.

  9. Rudolphine Tables - Wikipedia

    en.wikipedia.org/wiki/Rudolphine_Tables

    A scroll in the lower left panel of the map is inscribed with instructions on how to use the map and a lunar distance measurement to calculate longitude: it states that by observing the edge of the Moon's disc in relation to a known star, or a lunar eclipse, it is possible to calculate longitude at the point of observation by calculating local ...