quot;appears to be&quot; from the
   observer's location.

   As opposed to computing the apparent position of a target, one
   may wish to compute the pointing direction required for
   transmission of photons to the target. This also requires correction
   of the geometric target position for the effects of light time
   and stellar aberration, but in this case the corrections are
   computed for radiation traveling *from* the observer to the target.
   We will refer to this situation as the &quot;transmi