Removal of the detector artefacts. a) One of the chop-nod processed images of Antares, showing horizontal stripes. b) Same image as in a), after the removal of the horizontal stripes, as described in Sect. 2.2. c) Shift-and-added image of Antares obtained from all frames, in which the horizontal stripes are removed. The image shows an artefact that appears as the vertical regular pattern, whose amplitude is ~0.2% of the peak intensity of the central star. d) Same image as in c), after removing the vertical pattern, as described in Sect. 2.2.