te sensing instrument, such 
   as an optical camera or radio antenna, in order to observe or 
   otherwise receive radiation from a target.  This pointing problem 
   is complicated by the finite speed of light:  one needs to point 
   to where the target appears to be as opposed to where it actually 
   is at the epoch of observation.  We use the adjectives 
   &quot;geometric,&quot; &quot;uncorrected,&quot; or &quot;true&quot; to refer to an actual 
   position or state of a target at a specified epoch. 