Measurements of β using combinations of the 143 and 217 GHz Planck maps, normalized using Eq. (19)and then divided by the fiducial amplitude of β = 1.23 × 10^-3. These estimates use ℓ_min = 500 and ℓ_max = 2000. In addition to the total minimum variance estimate , the measurement is also broken down into its aberration-type part, , and modulation-type part, . Vertical lines give the Planck measurement for the four estimates described in the text. Grey histograms give the distribution of estimates for simulations of the 143 × 217 estimator, which do not contain peculiar velocity effects (the other estimators are very similar). The red histograms give the distribution for simulations which do contain peculiar velocity effects, simulated with the fiducial direction (along β_∥) and amplitude. Black triangles on the x-axis indicate the relevant component of f_sky given by Eq. (20), which agrees well with the peak of the velocity simulations.