The DART is a new telescope architecture consisting of a single aperture formed from two cylindrical parabolic reflectors . The system is ideally suited to using tensioned membranes for the reflective surfaces , owing to the zero Gaussian curvature of a cylindrical parabola . In this paper , we present experimental measurements for shaping the membranes by using curved boundary elements to achieve coarse shaping , and a pair of precision rails shaped by moments and forces at the ends , and lightly pushed into the surface , to provide fine shape control .