R_S   =  8.35 x 10^8  m

      r_orb = 6.96 x 10^9  m

      v_0   =  1.43 x 10^5  m/s


   Q:  For an absorption feature with rest wavelength 
             lambda_0 = 1.660 microns = 16,600 Angstroms,
             what is the shift in wavelength from ingress to egress?


          The shift from ingress to mid-transit is +0.95 Angstroms,
          and then from mid-transit to egress another +0.95 Angstroms.
          Therefore, the full shift from ingress to egress is
          a total of
  
                  +1.9  Angstroms  (redshift)