ht time correction.

                   'CN+S'     Converged Newtonian light time
                              and stellar aberration corrections.


                The following values of 'abcorr' apply to the
                &quot;transmission&quot; case in which photons *depart* from
                the observer's location at 'et' and arrive at the
                target's location at the light-time corrected epoch
                et+lt:

                   'XLT'      &quot;Transmission&quot; case:  cor