Wavefront evolution and contrast in the DH as a function of time in open-loop (first 900 s) and closed-loop (last 900 s) configurations under artificial drift conditions. An additional random perturbation of ten Zernike modes combined with 0.79 nm RMS on average is applied every 2 s. This amounts to a total aberration of about 25 nm RMS at the end of the 30-min experiment. Top: Zernike coefficients estimated with the inverse Jacobian matrix calibrated around SM commands. These have been artificially shifted along the vertical axis to enhance readability: all of them actually oscillate around zero in closed loop. Bottom: mean contrast in the DH in the case of a Jacobian matrix calibration performed around SM commands (continuous line) and around flat DM maps (dashed line).