This is a colour image of the galaxy cluster CL0024+1654 obtained with the CFHT12k camera at the Canada France Hawaii Telescope on Mauna Kea (Hawaii). The cluster clearly appears as a concentration of yellow galaxies in the centre of this image although cluster galaxies actually extend at least to the edge of this image. This image measures 21 x 21 arc-minutes.

Credit: European Space Agency, NASA, Jean-Paul Kneib (Observatoire Midi-Pyrénées, France/Caltech, USA) and the Canada France Hawaii Telescope