Moon: Lunar and Solar Eclipses

  • Albrecht Unsöld
Part of the Heidelberg Science Library book series (HSL)


The Moon appears to us as a disk with average diameter 31′and so with just about the same apparent size as the Sun. Its distance from the Earth can be got by triangulation from two observatories sufficiently far apart (say along the same meridian). Astronomers call the angle subtended at the Moon by the Earth’s equatorial radius the equatorial horizontal parallax of the Moon. Its value in the mean is 3422″.6. Since the Earth’s radius is known to be 6378 km, we derive for the mean distance of the Moon from the centre of the Earth
$$ 60.3\text{ Earth radii =384 400 km} $$
and hence for the radius of the Moon
$$ 0.272\text{ Earth radius =1738 km} $$


Solar Eclipse Photometric Observation Total Solar Eclipse Lunar Eclipse Gregorian Calendar 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag New York Inc. 1969

Authors and Affiliations

  • Albrecht Unsöld
    • 1
  1. 1.Institute for Theoretical Physics and University ObservatoryKielGermany

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