Relative systematic error on three parameters of the l = 0 − 2 and l = 1 − 3 multiplet as function of the fitted inclination angle: mode linewidth (solid line), mode height (dotted line), mode amplitude (dashed line) for a signal-to-noise ratio of 1. The multiplet has a nominal linewidth of 6 μHz and a nominal splitting of 4 μHz, with a nominal inclination angle of 45 degrees (left), and a nominal inclination angle of 90 degrees (right).