Comparison of the scattering angle of IC processes to separation of the two objects comprising PSR B1259–63/LS 2883. Left axis, green curve: The angle between the line-of-sight and the direction from the optical star at the pulsar’s location, as a function of time to periastron passage. If the production region is close to the pulsar, this angle is equal to the scattering angle for IC processes. Right axis, blue curve: The ratio of the separation distance, R, to the periastron separation. The shaded regions in this plot represent the periods of the sub spectra and are defined as in Fig. 4 (see Table 2 for the full details of these sub-periods).