Lomb-Scargle periodograms of the version (2) light curves presented in Figure 12, as well as of the window function of the observations. A multiplicative offset has been applied to each periodogram to render them all visible on the same plot. The window function has significant power at frequencies corresponding to 1/2 and 1/4 of SOHO's orbital period, because EIT does not take data during SOHO's keyhole periods, which occur twice per orbit. There is also excess power in the window function at 1/6 of SOHO's orbital period. All four light curves have excess power at the solar rotation period, while the window function does not.