ROSAT All Sky Survey (RASS) count image of Vela SNR in the 0.1−2.4 keV energy band in squared root scale. The circle K is the region analyzed in this work, marking the XMM-Newton field of view. The black cross indicates the position of the Vela pulsar at the explosion time by considering an age of 11 000 yr and taking into account the pulsar proper motion estimated by Caraveo et al. (2001). We assume it as the explosion center. The inset is a close-up view of the same image.