How to Make a Parabolic Mirror

The giant magellan telescope is one of the biggest mirrors that humans can make. It's made at a university in Arizona, which has a long and storied astronomy programm. They start with like, these chunks of glass, and they fill out this mould. And each one takes like years to make. Do you know about the process? Yhea, basical, theris only place in the world that can make these things.