The ninth satellite of Saturn, Phoebe, was discovered by W.H. Pickering in March 1899 from photographs made in 1898 at the Harvard observatory station, Arequipa, Peru (Pickering 1899). He subsequently published preliminary ephemerides for the satellite (Pickering 1905a,b). Ross (1905) produced the first definitive orbit based on observations made at Arequipa, Yerkes, and Lick in the early 1900s; Zadunaisky (1954) updated Ross' orbit using observations made between 1907 and 1942. Rose (1979) generated the first numerically integrated Phoebe orbit which he fit to observations over the period 1904 to 1969; he omitted those from Arequipa. Later integrations were done by Bec-Borsenberger & Rocher (1982) who fit observations from 1904 to 1981 and by Bykova & Shikhalev (1982, 1984) who fit observations from 1898 to 1981.
The purpose of this work is to update the orbit in light of recent astrometric observations and imaging observations obtained by the Voyager 2 spacecraft. Further incentive is provided by NASA's Cassini mission to Saturn (Kohlhase 1993). Current plans call for the Cassini spacecraft to pass by Phoebe at a distance of about 50000 km. A high quality ephemeris is needed to support scientific observations during this flyby.