7 Conclusions

The best fit in Table 6, $0\hbox{$.\!\!^{\prime\prime}$}025$, is between Titania and Oberon. We believe this fit is the best because these are the brightest two satellites. However, the typical error of centring a CCD image is $0\hbox{$.\!\!^{\prime\prime}$}012$ which should contribute $0\hbox{$.\!\!^{\prime\prime}$}017$ to the separation of two satellites. As all inter-satellite separations have bigger scatters than this we believe that the constants of the integration can be significantly improved on. Further observations are required which we plan to obtain.

Acknowledgements

The Jacobus Kapteyn Telescope is operated on the island of La Palma by the Royal Greenwich Observatory in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. The authors thank J.D.H. Pilkington for measuring the plates, R.W. Argyle for help with the photographic observations and A. Steele with the reductions. We thank L.V. Morrison for helpful advice.