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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. 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. 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 ...

  6. Hindu units of time - Wikipedia

    en.wikipedia.org/wiki/Hindu_units_of_time

    1 day (varies 19–26 hours) pakṣa (lunar fortnight) 15 tithis: ≈ 15 days māsa (lunar month) 2 pakṣas: gaura (bright) or śukla pakṣa during waxing moon; kṛṣṇa (dark) pakṣa during waning moon: ≈ 30 days (29.5 days) ṛitu (season) 2 māsas: ≈ 60 days ayanam: 3 ṛitus: ≈ 180 days varsha (lunar year) 2 ayanams: ≈ 360 ...

  7. Astronomical unit - Wikipedia

    en.wikipedia.org/wiki/Astronomical_unit

    Average distance from the Sun — Earth: 1.00 — 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: 7.2 — Distance light travels in one hour — Saturn: 9.5 ...

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

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

    The apparent size of the Sun and the Moon in the sky. The size of the Earth's shadow in relation to the Moon during a lunar eclipse; The angle between the Sun and Moon during a half moon is 90°. The rest of the article details a reconstruction of Aristarchus' method and results. [4] The reconstruction uses the following variables:

  9. 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.