Left: light curve from Fig. 2 for one halve orbit. Right: corresponding signal in the Fourier domain. The bottom horizontal axis are in steps of the (fast) lunar frequency. The top horizontal scale are in steps of the (slow) orbital frequency. The side structures that appear due to the eclipses are centered around multiples of Ω − ω. They are nearly identical copies of each other. Since the eclipse magnitudes of the two types are comparable (and the albedos are equal), the structures at odd m have almost disappeared. Noise would wash out the dips in the time domain and broaden these ideal Fourier peaks.