Dependence of the level of fit between the data and the model on the pole direction shown in sinusoidal projection of the sky in ecliptic coordinates. The reduced χ² is color-coded. There are two local minima for poles P1 and P2 (white circles). The estimated uncertainty of the poles is shown as two solid boundaries around P1 and P2. The uncertainty of the pole latitude β is much larger than that of pole longitude λ.