Top: dipole signal due to the motion of the solar system only (in Ecliptic coordinates). The points observed by LFI27M during pointing periods 4800 (250 days after launch) and 6636 (300 days) are shown with black and blue lines, respectively. (In Fig. 5, panel B on the right, we indicate the times when these two periods occurred with black dots.) Bottom: dipole signal along the same two pointing periods as a function of the North phase angle. Note the difference in the amplitude of the two sinusoidal waves. Such differences are due to the Planck’s scanning strategy and determine the statistical error in the estimation of the calibration constant K = G^-1 (Eq. (1)). Refer also to Fig. 9 for details about how K is computed for these two pointing periods.