Precession velocity of Ω and ω in the planetary regime. The colour represents the velocity scale from negative values in blue to positive values in red, with the same colour scale for Ω and ω. Both and attain their maximum absolute value at I = 0^o and 180^o. The locations where the integer combinations vanish (limited to ∥k∥, ∥j∥ < 3) are shown by horizontal lines. The inclination values on the left are obtained from Eq. (15), and the corresponding constant angles are written on the right.