Yellow curve, which is saturated in some peaks, shows the time variation of the SST seeing quality (Fried’s parameter r₀) as measured with the 120 × 120 WFS of the SST AO system, and the black curve shows the corresponding variations measured with a much smaller FOV of 40 × 40. The yellow curve corresponds roughly to ground-layer seeing and the black curve to a combination of ground- and high-altitude seeing (see text). We note the strong intermittency that requires high time resolution. The data were recorded on 13 May 2016.