This Video shows the process of the creation of a huge mirror for the World Largest Telescope.
Building a mirror for any giant telescope is not an easy task. The size of the glass, the nanometer precision of its curves, its carefully calculated optics, and the adaptive software required to run it make this a task of herculean proportions. But the recent castings of the 15-metric ton, off-axis mirrors for the Giant Magellan Telescope forced engineers to push the design and manufacturing process beyond all previous limits.
Credits: YouTube / IEEE Spectrum