That video was pretty wild. I didn’t understand at first what had happened when the silver layer got laid down and it was suddenly reflective
The 300T telescope movement assembly which can move the 300+ Ton telescope 3.5 degrees in 5 seconds, and the 3.2 GP camera especially are quite a bit harder to build, engineer, and integrate.
https://www.youtube.com/watch?v=c-lBKuHqHk0
Grinding and polishing is its own art.
https://www.youtube.com/watch?v=ebqeygLdBYc
None of this looks easy to me.