Hacker News Reader

Not this location, but the University of Arizona mirror lab does tours as well starting sometime next year: https://mirrorlab.arizona.edu/content/tours-tickets

They pour somewhat larger mirrors - most recent ones are 8.4 meters (330 inches) for the Giant Magellan Telescope.

View on HN

They spin their glass while melting it, which generates a parabolic surface that only needs polishing/coating. It's so very rad.

I've known people who did something similar with epoxy and an LP record player, but doing it with molten glass is next-level!

Check out this process: https://tucson.com/news/local/watch-now-ua-lab-casts-mirrors...

There are some other videos shot in the pandemic--it's a bit of good fortune that safety controls against silicosis are also super effective against respiratory pathogens.

These larger mirrors can also be made thinner now because their shape is actively controlled. They don't have to be as stiff as the mirror at Palomar, which was about at the upper limit for such mirrors (anything larger would sag too much retain its optical figure as the mirror was tilted.) Being thinner, these modern mirrors can be cooled more quickly.

Reply on news.ycombinator.com