Observed minus calculated (O–C) mid-transit times for HAT-P-26b in minutes. Red circular points show the values obtained from Hartman et al. (2011), Stevenson et al. (2016), and Wakeford et al. (2017). Black filled squares correspond to the values derived in this work considering complete transits, while empty squares are those derived from incomplete transits. The O–C diagram was computed using the best-fit orbital period derived in this work, specified in Table 3. The dashed black line corresponds to our best-fit sinusoidal variability.