GTC photometry of a transit of candidate KOI 806.02 in g′ (top) and z′ (bottom). The solid line is the fitted transit center and the dashed line its 3σ confidence limit, the shaded region defines the transit center  ± 3σ predicted by B11, and the dotted line is mid-way through the egress. The time of transit center predicted by the ephemeris of B11 is 2   455   740.5146 ± 4.2 × 10^-3, about 1.7h earlier. The lower figure shows the observed g′ − z′ during the transit egress, along with a modeled color signature using limb-darkening models from Claret & Bloemen (2011). The points shown are the mean of each 4 × 5 s exposure sequence.