Continuum-subtracted HST/STIS position-velocity (PV) plots of the jet from DG Tau, in [S ii]λ6731 emission in slit positions S1 to S7 (south-east to north-west). Contours are from 1.1 × 10^-15 erg s^-1 arcsec^-2 cm^-2 Å^-1 (3σ), with a ratio of 2^2/5. The solid lines mark the position of the star and zero velocity, while dashed lines mark the positions of identified features in images of this flow (see text).