Gray scale and contour PV maps of the [N II]λ6583 emission line. The gray levels and contours are logarithmic, the latter separated by a factor of two in linear intensity. The PA of each PV map is indicated and its position in the PV map marks the orientation of the slit, in agreement with the orientations of the slits marked in Fig. 3. Spatial and radial velocity scales are indicated in the PV map at PA +90°. The letters indicate the knots that are mainly covered by each slit (see Fig. 1) and the numbers are radial velocities (km s⁻¹) with respect to the systemic velocity of the nebula (Sect. 3.2).