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  2. Lunar distance (navigation) - Wikipedia

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

    Finding Greenwich time while at sea using a lunar distance. The lunar distance is the angle between the Moon and a star (or the Sun). In the above illustration the star Regulus is used. 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 ...

  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. Jet Propulsion Laboratory Development Ephemeris - Wikipedia

    en.wikipedia.org/wiki/Jet_Propulsion_Laboratory...

    The use of Chebyshev polynomials enables highly precise, efficient calculations for any given point in time. DE405 calculation for the inner planets "recovers" accuracy of about 0.001 seconds of arc (arcseconds) (equivalent to about 1 km at the distance of Mars); for the outer planets it is generally about 0.1 arcseconds.

  6. Free-return trajectory - Wikipedia

    en.wikipedia.org/wiki/Free-return_trajectory

    Sketch of a circumlunar free return trajectory (not to scale), plotted on the rotating reference frame rotating with the moon. (Moon's motion only shown for clarity) In orbital mechanics, a free-return trajectory is a trajectory of a spacecraft traveling away from a primary body (for example, the Earth) where gravity due to a secondary body (for example, the Moon) causes the spacecraft to ...

  7. History of longitude - Wikipedia

    en.wikipedia.org/wiki/History_of_longitude

    The lunar distance is the angle between a suitable star and the Moon. The dotted lines show the distances between Aldebaran and the Moon, 5 hours apart. Moon not to scale. "Lunars" or lunar distances were an early proposal for the calculation of longitude, having been first made practical by Regiomontanus in his 1474 Ephemerides Astronomicae.

  8. It’s Here: Your Complete 2025 Horoscope - AOL

    www.aol.com/complete-2025-horoscope-140000813.html

    For the first time since 2014, nomadic Jupiter boards a flight through Cancer, jetting through your worldly ninth house until June 30, 2026. ... plus a lunar eclipse on September 7. If you shoot ...

  9. Astronomical system of units - Wikipedia

    en.wikipedia.org/wiki/Astronomical_system_of_units

    It is approximately equal to the mean Earth–Sun distance. It was formerly defined as that length for which the Gaussian gravitational constant (k) takes the value 0.017 202 098 95 when the units of measurement are the astronomical units of length, mass and time. [1] The dimensions of k 2 are those of the constant of gravitation (G), i.e., L 3 ...