nation angles derived using an
                  ellipsoidal reference surface:
                      Phase angle              (deg):  101.659102
                      Solar incidence angle    (deg):  0.423140
                      Emission angle           (deg):  101.536837


 </PRE>
<h4><a name="Restrictions">Restrictions</a></h4>
<PRE>
 
   1) The solar illumination state indicated by the output argument `lit' 
      is computed treating the sun as a point light source. Surface
      points that are illu