NIR colour-magnitude relation for potential cluster members is plotted. Grey points are galaxies cross-matched between the DECam DR10 and VIRCAM catalogues, while red circles are those corresponding to literature redshifts used to create the best fit (blue) in the J − K versus K-band plot. The NIR J − K colour is used as a redshift proxy since cluster galaxies have similar colours. Targets within 2.5σ of the fit (dark grey region) are considered potential cluster members and form the IMACS target catalogue.