Central 20″ × 20″ field of 0540 as viewed by HST/WFPC2/F673N (left, positive) and NTT/EMMI/[O III]/0 (right, negative). North is up and east to the left. The contours of the Chandra/ACIS X-ray fluxes in Fig. 2 are overlaid in both images. The spatial distribution of the X-ray emission shows an elongated structure with NW-SE jets, which is associated with the PWN (cf. Serafimovich et al. 2004; Lundqvist et al. 2011). As seen, the [S II] emission dominating in the HST image does not extend outside the PWN, whereas the [O III] glow in the NTT image extends far outside the PWN.