Astrometric observations of the main Saturnian satellites from 2004 to 2014 based on Gaia DR3

Abstract

A total of 3169 astrometric positions of the seven main satellites of Saturn: Enceladus, Tethys, Dione, Rhea, Titan, Hyperion and Iapetus were obtained in the time span 2004–2014 from observations made with 1.56 m telescope at Sheshan station of Shanghai Observatory, CAS. We compared our observations to the theoretical positions retrieved from IMCCE ephemeris online service with satellite ephemeris of Lainey (2015) model and planetary ephemeris DE441. The mean residuals are between −25 mas and 39 mas in right ascension and declination, respectively. The positional standard errors are in the range 62–99 mas. Moreover, we also compared two recent orbit models of each satellite as well as three different planetary ephemerides of Saturn. These comparisons show that the differences among all the three planetary ephemerides are small.