Left: overlapping pupils in the HiCAT-segmented CLC configuration, and their diameters, used for the PASTIS experiments, projected in the pupil plane of DM1 (simulated image). The entrance pupil mask (bright green, undersized polygon shape) traces the outline of the IrisAO (dark green polygon shape) with a 97% undersizing factor, preventing the illumination of areas outside of the controllable segments. The entrance pupil diameter, D_pup (white dashed line), is defined as the circumscribed circle around the undersized pupil mask. The LS (yellow ellipse) is sized such that its edges stay within the controllable outline of the IrisAO. Since HiCAT uses reflective optics, the resulting beam foreshortening along the x axis results in all pupils being optically “squished” along the x direction. This is true for all optics and is immediately visible in this figure as the yellow LS surface is slightly elliptical with respect to the circle denoting its nominal diameter, D_LS (dashed black line). Right: measured pupil image on hardware with a detector located in a pupil plane before the two continuous DMs and the LS, showing the IrisAO segments and the pupil mask outlining the segmented DM. We note the slightly undersized outline, which results in somewhat irregular hexagons at the edges, especially noticeable on the six corner segments.