Absolute proper motions (cones) of the CH₃OH maser features (numbers) in IRAS 20126+4104. Numbers without an associated cone have been detected only over one or two epochs and the associated proper motion cannot be computed or is considered unreliable. Note that the all features are displayed at the positions of the first epoch (November 6, 2004). For features undetected at this epoch, the positions were obtained by extrapolation assuming they are moving with the mean absolute proper motion of the other features (in all cases the correction is  <10 mas). Absolute proper motions have been corrected for parallax, motion of the Sun with respect to the LSR, and Galactic rotation adopting a flat rotation curve as explained in Sect. 2. Most of the mean residual proper motion (~18 km s^-1) is believed to be due to deviation of the source from the assumed rotation curve. The maser features are identified by the numbers given in Col. 1 of Table 1, while their colour indicates the LSR velocity according to the scale displayed to the right. The two arcs schematically outline the Keplerian disk (Cesaroni et al. 2005), whose center lies out of the figure, to the SW.