Seasonal variation of the brightnesses towards the NEP (circles) and SEP (squares). We collected the brightnesses within from each of the poles and then took averages at 5° intervals of the Earth’s heliocentric ecliptic longitude. The blank points are excluded from the analysis, because the NEP brightness is contaminated by the Earthshine (longitudes from 225° to 320°) or the planetary nebula NGC 6543 (from 320° to 360°). The error bars are drawn for all the points, but most of them are too small to stand out.