
How do you build a mirror for one of the world's biggest telescopes? - dsr12
https://theconversation.com/how-do-you-build-a-mirror-for-one-of-the-worlds-biggest-telescopes-49927
======
hanniabu
These a How It's Made episode on building 30ft mirror. From a mechanical
engineering background, I must say that it's a truly amazing process. Tried
looking it up but was unfortunately unable to find.

~~~
3princip
The video in this article is also fascinating.

------
IvyMike
The use of silly putty as a self-shaping polishing disk is ingenious.

Link from the article: "Rigid conformal polishing tool using non-linear visco-
elastic effect"
[https://www.osapublishing.org/oe/abstract.cfm?uri=oe-18-3-22...](https://www.osapublishing.org/oe/abstract.cfm?uri=oe-18-3-2242)

------
DanBC
If you're interested in the handling of very large telescope mirrors (8
meters) here's a nice video of the mirror from the very large telescope array
in Chile being removed, transported, cleaned, re-surfaced, and put back.

[https://www.youtube.com/watch?v=CkV8RRRu7gE](https://www.youtube.com/watch?v=CkV8RRRu7gE)

------
vlehto
"A mirror much larger than eight meters, made of a single piece of glass,
would be too expensive and too hard to handle."

Glass was used 20 years ago because it has favorable stiffness to weight
ratio. Change to carbon fiber was speculated, but it's not transparent and it
would be more difficult to polish. Carbon fiber backed glass might be the
future.

