Square root of the CRLB in mas as a function of detector pixel size Δx in arcseconds for moving sources with e⁻ and where is given by Eq. (9) with b = 2000e⁻/arcsec, D is zero, and RON = 5e⁻. The FWHM is equal to 1.0′′. The three sets of curves correspond (from bottom to top) to a source drifting equal to 1.0′′, 2.0′′, and 3.0′′, respectively. Within each set, each line corresponds to a specific value of decentering between − 0.45 pixel (dotted lines) and 0 pixel (dashed lines).