Power spectrum of the t_reion(r) field obtained for ζ30. k is the spatial frequency with dimension [cMpc⁻¹ h]. The black line stands for the average power spectrum of the ground truth and the dotted coloured lines stand for P(k) predictions with different z_obs. The shaded areas depict the dispersion around the median (1st and 99th percentiles) for both predictions and ground truth.