Model fitting results of the kinematics for knot C2. Within core separation r_n < 1.47 mas, ψ = constant = − 2.097 and knot C2 moves along the modeled precessing common trajectory. In the upper left panel the dashed red line (modeling the entire trajectory) and the solid black line (modeling the inner trajectory) coincide within core separation r_n < 1.47 mas, showing a small curvature in its outer trajectory. In the upper right panel two additional modeled trajectories calculated for t₀ ± 0.5 yr (or ϕ ± 0.61 rad) are added todemonstrate that most of the observation data points are within the position angle range defined by the two additional modeled trajectories (green and magneta lines) and the precession period is determined within an uncertainty of ~ ± 0.5 yr.