Mean intensity (〈I〉, top), projected Rayleigh statistic (V, middle), and derivative kernel size (Δ, bottom) for 3° × 20° × 1.29 km s⁻¹ toward the indicated positions. The two lines in the middle panel indicate the results obtained with a derivative kernel with a fixed angular size and a kernel with a fixed physical size, as indicated on the legend. The kernel with a fixed physical size is exclusively used in the radial velocity range corresponding to kinematic distances where the angular size of the kernel is below 1°.