DETECTION OF A DISTANT CLUSTER IN THE CENTER OF THE SHEAR FIELD IN Q 2345+007

We report on the detection of an excess of faint blue galaxies located in the center of the shear field detected by Bonnet et al. (1993). By using ultra-deep B and I CCD images obtained at the prime focus of CF HT, we computed isopleth contour maps by color intervals and found an excess of blue galaxies exactly centered on the center of the shear fi eld (found by Bonnet et al.), with a small additional clump close to t he double quasar. The angular size of the region with the density exce ss, as well as the color and surface brightness of the galaxies are ev idences that we have detected a cluster of galaxies at redshift larger than 1. The faint blue galaxies are not distorted (no detectable shea r) as expected for a lens responsible for the shear pattern. We discus s the consequences on the distance of the faintest sheared galaxies an d on the usefullness of the weak shear technique for cosmology.