 phi is given by

            sin(phi) = v sin(w) / c

         Let h be the vector given by the cross product

            h = r X v

         Rotate r by phi radians about h to obtain the apparent
         position of the object.

      When stellar aberration corrections are used, the rate of change
      of the stellar aberration correction is accounted for in the
      computation of the output velocity.


      Transmission case
      ==================

      When any of the options &quot;XLT&quot;, 