Azimuthally averaged power spectra for relevant observations shown in Sect. 6. The average is only performed for angles in the Fourier plane with −45 ± 15^° and 45 ± 15^°. The vertical line marks the diffraction limit. Note that the power spectrum is computed in the full FoV, so that some high-frequency artifacts can appear when the FoV is built from mosaicked patches. To avoid showing noise-dominated artifacts, the power below an estimated noise floor (noise level per frame divided by the number of frames) is not displayed.