CCD Astrometric Observations of Phoebe in 2005-2008

International audienceAstrometric observations of Phoebe, the ninth faint satellite of Saturn with vi-sual magnitude of 16.5, were performed during the four successive 2005, 2006, 2007 and 2008 oppositions. A very important amount of 1173 new observed positions of Phoebe, representing more than 50 percent of the observational data available now, were obtained during 30 nights of observation involving six missions, by using three different telescopes. The comparison of our observed positions with the JPL Phoebe ephemeris shows the high quality of our observations, as they appear to be consistent with this ephemeris within only about 50 mas