Details of some SPHERE2017 astrometric observations and converged models with no tides (top) and including tides (bottom). The assumed uncertainties (10 mas) are indicated by black circles, and residuals are shown as red or orange lines. There is a noticeable improvement for the first moon. However, the second moon is still offset, possibly because of some remaining systematic error. The proper motion in the (u, v) plane is relatively slow because of the orbit orientation and the line of sight.