 Its surface features include large craters and ridges.Close range images of Amalthea were taken in 1979 by the "Voyager 1" and "2" spacecraft, and in more detail by the "Galileo" orbiter in the 1990s.Amalthea was discovered on 9 September 1892, by Edward Emerson Barnard using the 36 inch (91 cm) refractor telescope at Lick Observatory.