Euler r-band and TRAPPIST “I + z”-band follow up high signal-to-noise photometry of WASP-57 during the transit (see Table 2). The TRAPPIST light curves have been offset from zero by an arbitrary amount for clarity. The data are phase-folded on the ephemeris from Table 5. Superimposed (black-solid lines) are the best-fit transit models estimated using the formalism from Mandel & Agol (2002). The residuals from each fit are displayed underneath the relative light curves.