Left: relative deviation of the spline-interpolated limb darkening predictions for N_μ = 17 (solid line) and N_μ = 51 (dotted line) from the case with N_μ = 101 as a function of μ. Grey vertical lines mark the position of the 17 μ angles used in the “standard” resolution. Right: relative deviation of the least-squares-fitted limb darkening laws from the computed data points for N_μ = 17 (crosses), N_μ = 51 (diamonds) and N_μ = 101 (triangles) as a function of μ. All calculations are based on the 3D model of HD 189733.