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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 ...
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.
Lunar distance (LD), the distance from the centre of Earth to the centre of the Moon, is a unit of measure in astronomy. The lunar distance is approximately 384,400 km (238,900 mi), or 1.28 light-seconds; this is roughly 30 times Earth's diameter. A little less than 400 lunar distances make up an astronomical unit.
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 ...
Length; system unit code (other) symbol or abbrev. notes conversion factor/m combinations SI: gigametre: Gm Gm US spelling: gigameter: 1.0 Gm (620,000 mi) megametre: Mm Mm US spelling: megameter: 1.0 Mm (620 mi) kilometre: km km US spelling: kilometer: 1.0 km (0.62 mi) km mi; hectometre: hm hm US spelling: hectometer: 1.0 hm (330 ft) decametre ...
The term "unit distance" is also used for the length A while, in general usage, it is usually referred to simply as the "astronomical unit", symbol au. An equivalent formulation of the old definition of the astronomical unit is the radius of an unperturbed circular Newtonian orbit about the Sun of a particle having infinitesimal mass, moving ...
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 ...
Lunar distance LD ≈ 384 402 km. [15] Average distance between the center of Earth and the center of the Moon. astronomical unit au. Defined as 149 597 870 700 m. [16] Approximately the distance between the Earth and Sun. light-year ly ≈ 9 460 730 472 580.8 km. The distance that light travels in a vacuum in one Julian year. [17]