On-board photometry performed with the optimal aperture algorithm of Marchiori et al. (2019) for a V = 10 star. With a central barycentric pixel position and a (worst case) systematic drift of 1.3 pixel over the course of one mission quarter, the figure shows the algorithm in action with the automatic pixel-mask updates triggered every 14 days (grey-dotted lines) if a lower NSR can be achieved (which is not the case for the update at 42 days). Since the NSR does not scale linearly with flux, the mask-update strategy does not necessarily increase the flux level (as the case at 28 days). The positive flux outliers are due to contamination from cosmic rays (with a hit rate of 10 events s⁻¹ cm⁻²).