 Amalthea was discovered on 9 September 1892 , by Edward Emerson Barnard using the 36 inch ( 91 cm ) refractor telescope at Lick Observatory . It was the last planetary satellite to be discovered by direct visual observation ( as opposed to photographically ) and was the first new satellite of Jupiter since Galileo Galilei 's discovery of the Galilean satellites in 1610 . 
