Galactic Na i absorption toward PKS 1229−02: spectrum, its error (red curves) and simultaneous fit to both transitions (blue curve). The UVES 2002 data are shown in the top panel; in the bottom panel we display the UVES 2011 data together with the fits to the 2002 data (blue). Note the disappearance of the component at v_helio = 9.6 km s^-1 (thick vertical tick mark), within a period of 9.2 yr. The heliocentric redshift z = −0.000159 (strongest component) corresponds to v = 0 km s^-1.