The theory of charged particle motion in a dipole field has been well developed, however because of the importance to the geomagnetic field of contributions other than dipolar, interest in the subject has remained primarily pedagogical over the past decade. Recent measurements by Ness et al. and Smith et al. have shown that the magnetic field of Saturn is essentially dipolar, with the axis of the dipole approximately aligned with the planetary rotation axis. This note briefly sketches the dipole geomagnetic cutoff theory and demonstrates the scaling required for its applicability to energetic particle measurements in the vicinity of Saturn.