5 Comparison with the theories

The observed relative positions of the satellites were compared with the calculated positions deduced from the above-mentioned four contemporary theories; for TASS we used a revised new version TASS1.7 (1997). Validity of TASS has been preliminarily examined by Shen & Qiao (1995). These theories fitted well to all the known observations in the past. The orbital elements of the satellites corresponding to these theories were taken from their respective paper. Table 3 gives the rms of the residuals for each of the satellite pairs obtained from the four reductions made. It appears that we have obtained the anticipated results, most of the observations have an rms of about 0.08 arcsec except a few faint satellites, which are slightly poorer. For each of the satellites there is better agreement in rms of the residuals obtained from each of the four reductions made, while for those faint satellites where the accuracy is not so good, they seem to be reasonable.