fixed frame and
         % the aberration correction flag.
         %

         target = 'Mars';
         obsrvr = 'MGS';
         ilusrc = 'Sun';
         fixref = 'IAU_MARS';
         abcorr = 'CN+S';

         ilumth  = {'Ellipsoid', 'DSK/Unprioritized' };
         submth =  {'Near Point/Ellipsoid', 'DSK/Nadir/Unprioritized' };

         for i=1:numel(ilumth)

            %
            % Find the sub-solar point on the Earth as seen from
            % the MGS spacecraft at et. Use the 'near point'
      