About 500 photographic plates of the Galilean satellites made with the 26-inch refractor of USNO in Washington DC from 1967 to 1998 were digitized and reduced using the UCAC2 star catalog. Results on the ephemerides of the Galilean satellites and on the determination of the mass of Amalthea will be presented. An evaluation of the accuracy of several ephemerides of Jupiter on the 1967-1998 period will also be provided.