Phobos was discovered astronomer Asaph Hall, Senior, 18 August 1877, the U.S. Naval Observatory in Washington, DC, at approximately 09:14 UTC (modern sources, using the pre-1925 astronomy convention, which began the day at noon, give time of discovery, as the August 17, 16:06 Washington Mean Time). [7] [8] [9] Hall also discovered Deimos, "Mars' other moon.
The names, which were originally written Phobus and Deimus, respectively, were suggested by Henry Madan (1838-1901), Master of Science Eton XV of the books in the Iliad, where Ares summons fear (Deimos) and Fear (Phobos).