Photometric measurements of the star C, relatively to star A in Kcont (red symbols) as a function of the orbital phase of the S3 curve. Plotted over is the model S3 curve, corrected for the third light. The two measurements are shifted by 5.11 mag to match the model curve at the phases of observations. The unfortunate timing of the runs did not allow us to verify if the star C is the S3 eclipsing binary, even if the expected secondary eclipse is deeper in Kcont than in the Kepler band.