Upper panel: modeled distribution of the trajectory of the precessing nozzle model for the inner jet regions. ϕ = 1.0, 2.0, 3.0, 4.0, 5.0, and 6.0 rad. The common trajectory rotates around the precession axis anticlockwise viewed along the axis. The precession axis is at position angle of 30.1°. Middle panel: distribution of the observed trajectories of knots C1–C6 in the plane of the sky. Bottom panel: model fitting of the core separations for knots C1–C6. The model fitting of their kinematics are shown individually in Figs. 5–10.