1997–2000 CCD astrometric observations of Saturn's satellites and comparison with theories

Abstract

As a continuation of the observing campaign 1994-1996 (Qiao et al. 1999), this paper presents 1167 new measure- ments of the positions of the major Saturnian satellites obtained using a CCD camera on the 1.56 m reflector at the Sheshan station near Shanghai during the period 1997-2000. The observations include the major satellites exclusive of the faintest satel- lite, Hyperion. The analytical theory TASS was chosen for astrometric calibration of the CCD and theory computation. Analysis of the data as inter-satellite positions shows that the observations of Tethys, Dione, Rhea, and Iapetus have a standard deviation about the mean of 0. �� 06, which matches the accuracy of our earlier observations. However, for a few of the inner satellites, including Mimas, Enceladus, we have obtained poorer residuals up to 0. �� 1t o 0. �� 2 which we ascribe to lower quantum efficiency of the CCD.