Red-green-blue image composition of HST images of the part of AS1063 that we observed with MUSE, where the colours in this image are blue = F435W + F475W, green = F606W + F625W + F775W + F814W + F850LP, red = F105W + F110W + F140W + F160W. The individual HST images were obtained and distributed by the CLASH collaboration. The green square delimits the 1 × 1′ MUSE FOV. All 19 objects with a spectroscopic redshift z> 1 are shown as white circles and their redshifts. Numbered galaxies were noted before by Monna et al. (2014) and Balestra et al. (2013). The blue, magenta, and red contours correspond to regions where the magnification is μ> 200 at z = 1, 2, and 4, respectively. The magnifications are based on the second version of the Sharon models (Johnson et al. 2014), which were chosen for illustrative purposes, but we note that this is only one out of many different available models.