Amalthea was discovered on 9 September 1892, by Edward Emerson Barnard using the 36 inch (91 cm) refractor telescope at Lick Observatory.
Amalthea upptäcktes den 9 september, 1892 av Edward Emerson Barnard som använde det 36 tum (91 cm) stora refraktorteleskopet vid Lick Observatory.