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Discoveries > Mars VII


Credit : F. Colas, J. Lecacheux/ observatoire du Pic du Midi/CNRS 
To show the satellites on a CCD Image saturated by the light of Mars, image processing is necessary: one can easily see the fast motion of the two satellites around Mars.

The satellites of Mars were discovered by Asaph Hall in Washington DC in 1877 with a large refractor. These satellites are small, very close to Mars and difficult to observe. Their nature suggests that they are asteroids captured by Mars. 

Although they have been observed in 1877, astronomers expected before to find satellites around Mars. In 1643, A. Shyrl claims to have seen satellites around Mars: but with telescopes of the time, it was impossible. In 1727, Jonathan Swift in the "Gulliver's Travels", indicates that the Lilliputian astronomers have observed two satellites around Mars with periods of 10 hours and 21 hours. Amazingly these periods are close to the actual periods being 8 hours and 30 hours.