Different notation systems for the knots of ESO-Hα 574 found in the literature. Left: HST WFPC images of ESO-Hα 574 published in Robberto et al. (2012). For the purpose of this figure we obtained the reduced image from the HST archive¹. Right: position-velocity diagram of the ESO-Hα 574 jet in Hα made from our X-Shooter data and first published in Bacciotti et al. (2011). In this paper we follow the notation of Bacciotti et al. (2011).