Top: model STFs computed using β from Fig. 1 under different input values of r₀ in cm (colored) for the 10 cm (left) and 15 cm (right) atmospheric simulations. Also shown: diffraction-limited squared MTF (dotted), pre-AO atmospheric STF_sim (dashed), and post-AO corrected STF_sim (solid black). Bottom: resulting image photometric error for the two image scenes. The AO-estimated value of r₀ is shown as the dashed vertical line. The 2% target value for DKIST is marked with the horizontal line.