Jim Message
             Department of Applied Mathematics and Theoretical Physics,
                                   University of Liverpool,        
                                     P.O. Box 147,
                                         Liverpool, L69 3BX,
                                             England

          "On the theory of the motion of the orbit plane of Hyperion"

                Investigation of the equations governing the parameters
of the orbit plane of Hyperion show the existence of a series of terms of 
very long period.       The orbit plane of Hyperion remains always very
close to that of Titan, which makes it quite difficult to determine the 
free parameters of the orbit plane motion from observation.  
Values of these parameters from analysis of the older observations are
consequently only quite approximate, and so the periods of some of the 
long-period terms can be only approximately calculated.      It is hoped
that, in due course, analysis of later, more precise, observations will 
provide improved estimates.