Asaph Hall, Sr. at the United States Naval Observatory in Washington, D.C discovered Phobos on August 18, 1877, at about 09:14 GMT, after deliberately searching for Martian moons.
Asaph Hall III (October 15, 1829 - November 22, 1907) was an American astronomer who is most famous for having discovered the moons of Mars (namely Deimos and Phobos) in 1877. Read more