Residuals of the timings of mid-transit of HAT-P-26 b versus the linear term in the sinusoidal ephemeris. The dotted blue line shows the sine curve and the points represent the residuals of the measured transit times versus the linear term in the ephemeris. Filled green circles are data from von Essen et al. (2019), black circles are the other timings from the literature that are also reported in von Essen et al. (2019), and red squares are the new timings from this work. Empty circles refer to mid-transit times estimated from incomplete transit light curves. The errorbars of the timings coming from incomplete HST light curves were increased (see text).