Abstract The Major Atmospheric Gamma Imaging Cherenkov telescope will achieve an energy threshold lower than any other present IACT (E Th ∼30 Gev ) thanks to the largest reflecting surface, a 17 m diameter, f/1, tessellated parabolic reflector. The tiles are 50 cm ×50 cm all-aluminum spherical mirrors with different radii of curvature to best fit the paraboloid. The technology used to make these mirrors and the method used to measure their optical properties, as the focal length, the spot size and the reflectivity, are described. The results of these measurements are shown.