Reduced χ² of the moment expansion fits as a function of the multipole ℓ. From the top left to the bottom right, the panels show the χ²(ℓ) results for the SIM1 (green circles), SIM2 (yellow squares), SIM3 (red diamonds), SIM4 (blue stars), and PR3 (black triangles) data sets. The χ²(ℓ) of the fits at zero (solid black), first (dashed yellow), second (dashed-dotted blue), and third order (dotted red) are displayed.