Colour-composite image of SDSS 2222 obtained by combining the F435W (blue), F814W (green), and F160W (red) HST passbands. The ∼ 1 arcmin² MUSE footprint is shown in green. The galaxies with a secure MUSE redshift measurement (QF ≥ 2) are highlighted with colour-coded circles. Cluster galaxies are identified in blue (three cluster members outside the MUSE field of view are included in the SDSS DR9 catalogue); those with a reliable measurement of their stellar velocity dispersion in red; and foreground and background objects in cyan and magenta, respectively. The multiple images are shown in Fig. 4.