Measurements of Δα/α in the z_abs = 1.1508 absorber towards HE 0515−4414 (blue points), and recent measurements which were corrected for, or insensitive to, wavelength calibration errors (orange points). The shaded patches show the values included in the weighted mean values indicated by arrows and dotted lines. For each study, the number of absorption systems, N_abs, number of independent Δα/α measurements (for the entire absorber), N_meas, and absorption redshift or range, z_abs, are shown in the right-hand panels. Shorter, thicker error bars indicate 1σ statistical uncertainties while the longer error bars with taller terminators show the quadrature sum of statistical and systematic uncertainties.