The mutual events of the Galilean satellites in 1985-1986

Nearly 300 observable mutual occultations and eclipses of the Galilean satellites are expected to occur between May 1985 and April 1986. Here, predictions for 252 of the forthcoming mutual satellite phenomena are presented which are based on Lieske's (1978, 1980) refinements of Sampson's theory of the motions of the Galilean satellites. It is noted that a series of precisely timed events observed over a sufficiently long baseline has the potential of detecting secular changes in Io's orbital elements arising from tidal interaction. The current apparition also provides an opportunity for improving satellite ephemerides to assist in guiding the Galileo spacecraft during several extremely close approaches.