team, however, showed a high-quality aspect reconstruction for the Vela observations.

Further analysis by the HRC team revealed a systematic problem with one of the three anode preamplifiers which causes the coarse position algorithm to mis-place photon locations depending on the photon input position relative to the HRC tap gaps. This explains the apparent wandering of the pulsar centroid at the dither frequency: a fraction of the detected photons are displaced along the detector coordinates by a fixed amount. Indeed, we were able to ascertain that the apparent diffuse flux was produced by faint echoes of the pulsar itself along the two orthogonal detector axes [^1].

To eliminate the echoes, we initially used the bright pulsar as a fiducial point to re-aspect the photons and thus take out the detector-induced wobble in a statistical sense. Subsequently, the instrument team made available a beta version of a code to identify and correct the mis-placed photons – [HRC\_EVT0\_CORRECT]{} – along with updated degap parameters ($cfu1=1.068$; $cfu2=0.0$; $cfv1=1.045$; $cfv2=0.0$) for use in [HRC\_PROCESS\_EVENTS]{}. This software, together with the new parameters, effectively eliminated the echo problem. The images produced by the two methods are indistinguishable and the pulsar now matches the PSF to within 