th(i), ...
                                           target, et, fixref, ...
                                           abcorr, obsrvr );

            %
            % Find the phase, solar incidence, and emission
            % angles at the sub-solar point on the Earth as seen
            % from MGS at time et.
            %
            [ trgepc, srfvec, sslphs, sslsol, sslemi, sslvis, ssllit] = ...
                           <b>cspice_illumf</b>( ilumth(i),   ...
                                          