on is 
 
         T(et) - O(et) 
 
 
      Reception case 
      ============== 
 
      When any of the options &quot;LT&quot;, &quot;CN&quot;, &quot;LT+S&quot;, &quot;CN+S&quot; is selected
      for `abcorr', <b>spkpos_c</b> computes the position of the target body at
      epoch et-lt, where 'lt' is the one-way light time.  Let T(t) and
      O(t) represent the positions of the target and observer 
      relative to the solar system barycenter at time t; then 'lt' is 
      the solution of the light-tim