Upper panel: linear density of the trailing tail, as a function of the distance from the cluster center, for different orbits having the same radial velocity of the standard orbit (S.O., black line), i.e. −44.3 km s^-1, and v_t = 80 km s^-1 (blue line), v_t = 89 km s^-1 (magenta line), v_t = 91 km s^-1 (green line), or v_t = 110 km s^-1 (red line). Lower panel: the same but for orbits having the same tangential velocity of the standard orbit (S.O., black line), i.e. 90 km s^-1, and v_r = −42 km s^-1 (blue line) or v_r = −46 km s^-1 (red line). The typical Poisson’s uncertainty is shown.