Color image of A1689 obtained by combining F475W, F775W, and F850LP HST/ACS images using a logarithmic scale, showing a 3.7′′× 2.45′′ region around 944 and LN22. Circles have diameters of 0.60′′, which is close to the FWHM seeing measured in the MUSE data. Cyan isocontours display flux levels for Lyman-α emission from 0.3 to 8 × 10^-19 erg/s/cm²/pix², with bins of 1.25 × 10^-20 erg/s/cm²/pix². The brightest source seen in the HST image is likely to be a cluster galaxy, but no spectroscopic redshift could be determined for it.