f="dasopr_c.html">dasopr_c</a>.
 

   et          is the epoch, represented  as seconds past J2000 TDB, at
               which the illumination angles are to be computed.  When
               aberration corrections are used, `et' refers to the
               epoch at which radiation is received at the observer.
 
   abcorr      indicates the aberration corrections to be applied to
               the position and orientation of the target body and the
               position of the Sun to account for one-wa