Fig. 1

Illustration of the frame selection on the PSF calibrators HD 187642 (top) and HD 169414 (bottom) for the PAH-1filter. The full distribution is given by the filled + empty symbols. The filled squares correspond to the frames finally selected. The dashed line is the theoretical diffraction limit of the telescope at 8.6 μm. The FWHMis estimated by fitting of a Lorentzian function.
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