Don't think that the application of carbon fiber in astronomical telescopes is just a carbon fiber barrel. In giant telescopes, carbon fiber tubes can also be used for mirror backs. For example, the Yangbajing Observatory Zhongdeya Millimeter Wave Telescope, known as the “eye of space” in Tibet, is a space truss made up of 162 carbon fiber tubes connected by 46 Invar bolt balls. This optimized structural design and material selection takes into account the thermal expansion (the overall thermal expansion coefficient of the back frame is zero) and stiffness, ensuring that the surface accuracy of the primary mirror remains within 10 μm (rms) under rated load and thermal cycling conditions. stability.