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Events on Saturday 18 August 1877 1
1877Phobos and Deimos discoveredAsaph Hall identifies Mars's two moonsAmerican astronomer Asaph Hall discovered Mars's two small moons using the US Naval Observatory's refracting telescope, finding Deimos on 12 August 1877 and Phobos six days later. He named them after the mythological attendants of the war god Ares. They remain the only known natural satellites of Mars.