Isocontour plot on an Aitoff projection of the differences in radial velocity due to Galactic rotation from Eq. (5)for test values of calculated using Eq. (24)and the values in Table 1. The gradients of the velocity dispersion tensor are treated as in Vallenari et al. (2006). The assumed values for the motion of the Sun relative to the LSR are from this paper. The yellow points show the RAVE data selection from Sect. 2.1. The black contour lines represent the limit of 14 km   s^-1 adopted in our paper.