a GPS receiver). Other experimental methods of measuring the lunar distance that can be performed by amateur astronomers involve: Taking pictures of the Moon before it enters the penumbra and after it is completely eclipsed. Measuring, as precisely as possible, the time of the eclipse contacts. Taking good pictures of the partial eclipse when the shape and size of the Earth shadow are clearly visible. Taking a picture of the Moon including, in the same field of view, Spica and Mars – from various locations. See also Astronomical unit Ephemeris Jet Propulsion Laboratory Development Ephemeris Lunar Laser Ranging Experiment Lunar theory On the Sizes and Distances (Aristarchus) Orbit of the Moon Prutenic Tables of Erasmus Reinhold Supermoon References External links Wolfram Alpha widget – Current Moon Earth distance Orbit of the Moon Units of measurement in astronomy Units of length