Top: amplitude | β | of the Doppler boost from the SEVEM-100, SEVEM-143, and SEVEM-217 maps for different multipole bins determined using a BipoSH analysis. The maximum multipole of each bin is fixed at ℓ_max = 1024, while ℓ_min is incremented from ℓ = 2 to ℓ = 640 in steps of Δℓ = 128. The dashed line corresponds to the actual dipole boost amplitude, | β | = 1.23 × 10^-3. Bottom: Doppler boost direction measured in Galactic coordinates from SEVEM-217. The coloured circles denote ℓ_min used in the analysis, while ℓ_max = 1024 is held fixed. The low-ℓ and WMAP-9 directions are identical to those in Fig. 35.