Tail distribution functions (see the definition in the main text) of solar brightness variations as they would be measured by Kepler (solid curves), CoRoT (dotted curves in panel b)), and in Strömgren (b + y)/2 photometry (dotted curves in panel d)). Black, red, and blue curves correspond to total, facular, and spot light curves, respectively. The variations are measured by R_var(30 days) and are given in parts per thousand (ppt, 1 mmag ≈0.92 ppt). Plotted are the tail distribution functions calculated at four values of solar inclination: i = 90° (panel a)), i = 60° (panel b)), i = 30° (panel c)), and i = 0° (panel d)).