KnotsC1 and C6 have almost equal position angles and move along very similar trajectories, but their observed ejection times are 1991.58 ± 0.28 and 2007.31 ± 0.30, differing by 15.73 yr. If this similarity of the position angles at the two ejection epoches is caused by the jet precession, then its is argued that 15.73/3 = 5.24 yr is the most appropriate precession period. The dotted and dashed lines denote the modeledtrajectories for knots C1 and C6, respectively (see text).