The scatter in the measurement of the velocity as a function of S/N for individual stars. We use an isolated bright star in the halo field, with F814W = 22.58 and S/N = 14 as template. The vertical blue line is the radial velocity of the star obtained with pPXF of 12.2 km s⁻¹. In red we report the standard deviation at various levels of S/N, which decreases as the S/N increases.