Colour(r-i)-magnitude(r) diagram for ACTJ0240, created using SDSS data within 1.5 Mpc of the cluster centre. The grey circles depict all the galaxies found at the cluster redshift, within this region. The black solid line depicts the cluster red-sequence estimated using the galaxies with spectroscopic data (shown using orange squares) and the red circles depict member galaxies selected using this red sequence.