Original: Amalthea was discovered on September 9, 1892 by Edward Emerson Barnard using the 36 inch (91 cm) refractor telescope at Lick Observatory.
Simplified: It was found on September 9, 1892, by Edward Emerson Barnard and named after Amalthea, a nymph in Greek mythology. Amalthea was found on September 9, 1892 by Edward Emerson Barnard using the 36 inch (91 cm) telescope at Lick Observatory.