Fabrication of the SubReflector for the Large Millimeter Telescope (Gran Telescopio Milimétrico)

Astronomers use telescopes to study the universe in the different spectrum regions. The dimensions of telescopes, to research in the millimeter region, are too big. Thus, fabrication of such instruments is a challenge work. The “Gran Telescopio Milimétrico (Large Millimeter Telescope, which will be called LMT) is a Cassegrain Telescope, which diameter of the primary reflector is 50 meters and the subreflector is a hyperbolic surface which diameter is 2.57 meters, and it is been developed to observe in the millimeter region. The subrelector surface must be fabricated with an accuracy of 13 µm (rms). Furthermore, the subreflector must achieve the so-called wobbling, meaning that the subreflector cannot be so heavy, but enough stiff to be wobbled. In this work, we describe the fabrication technique for the subreflector.