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  2. 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 ...

  3. Lunar distance (navigation) - Wikipedia

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

    The altitudes of the two bodies are used to make corrections and determine the time. 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 ...

  4. 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 ...

  5. 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 ...

  6. On Sizes and Distances (Hipparchus) - Wikipedia

    en.wikipedia.org/wiki/On_Sizes_and_Distances...

    On Sizes and Distances (of the Sun and Moon) (Greek: Περὶ μεγεθῶν καὶ ἀποστημάτων [ἡλίου καὶ σελήνης], romanized: Peri megethon kai apostematon) is a text by the ancient Greek astronomer Hipparchus (c. 190 – c. 120 BC) in which approximations are made for the radii of the Sun and the Moon as well as their distances from the Earth.

  7. Lunar Laser Ranging experiments - Wikipedia

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

    The distance to the Moon is calculated approximately using the equation: distance = (speed of light × duration of delay due to reflection) / 2. Since the speed of light is a defined constant, conversion between distance and time of flight can be made without ambiguity.

  8. Lunar theory - Wikipedia

    en.wikipedia.org/wiki/Lunar_theory

    The most significant improvement of position observations of the Moon have been the Lunar Laser Ranging measurements, obtained using Earth-bound lasers and special retroreflectors placed on the surface of the Moon. The time-of-flight of a pulse of laser light to one of the retroreflectors and back gives a measure of the Moon's distance at that ...

  9. Astronomical unit - Wikipedia

    en.wikipedia.org/wiki/Astronomical_unit

    Average distance of Earth's orbit from the Sun (sunlight travels for 8 minutes and 19 seconds before reaching Earth) — Mars: 1.52 — Average distance from the Sun — Jupiter: 5.2 — Average distance from the Sun — Light-hour: 7.2Distance light travels in one hour — Saturn: 9.5 — Average distance from the Sun — Uranus: 19.2 ...