[bjpirt]

The timescales involved in the manufacture of this mirror are amazing. I love the way this guy just casually states things like:

"we then cool the glass ... for a few months"

"the mirror will sit for the next year while we machine the back surface flat"

"that final polishing process ... takes about 18 months"

It's kind of mind blowing for it to take so long to make a single object.

[woodandsteel]

>"that final polishing process ... takes about 18 months"

That's a lot faster than it used to be. The 200 inch mirror at Mt Palomar took 13 years to grind and polish. I guess they have greatly improved the technology.

https://en.wikipedia.org/wiki/Hale_Telescope

[mankyd]

I'm curious if its actually polishing for 18 months, or if its a few days of polishing, followed by a few days inspection, on and off.* I can't imagine they simply turn it on and let it run for a year and a half non-stop.

* Or some other tempo of alternation.

[nacs]

There were probably even longer timespans involved in planning and getting it approved by everyone.