Using Open-Loop Adaptive Optics to Measure Black Hole Masses

These plots demonstrate stability of the correction to the point spread function (PSF) using the open focus loop mode. The left panel shows the PSF of a star in standard closed loop mode. The right panel shows the corresponding PSF in with the focus loop open (and tip-tilt loop closed on the star) after an hour of open loop observations. The subsequent degradation in the PSF is negligible.