Normalized probability distribution functions of Δψ between Planck data at 353 GHz and the H I templates. The value of Δψ is computed for different sky masks at angular and pixel resolutions of 80' and N_side = 128, respectively. The NPDFs are shown for both Galactic hemispheres combined (central panels) and for the southern (left panels) and northern (right panels) hemispheres individually. The corresponding circular-mean values (in black circles) and their standard deviations (in gray diamonds) are shown in the insets at the bottom as a function of the sky mask. The gray shaded area in the middle panels represents the misalignment angle caused by systematic differences between SRoll2 and PR4 data.