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Old September 11th 18, 02:55 AM posted to sci.astro.amateur
RichA[_6_]
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Default Casting a $20 Million Mirror for the World’s Largest Telescope

On Monday, 10 September 2018 00:11:22 UTC-4, Chris L Peterson wrote:
On Sun, 9 Sep 2018 17:03:49 -0700 (PDT), RichA
wrote:

On Saturday, 8 September 2018 01:04:15 UTC-4, StarDust wrote:
https://www.youtube.com/watch?v=M2f4zepwcy8

Building a mirror for any giant telescope is no simple feat. The sheer size of the glass, the nanometer precision of its curves, its carefully calculated optics, and the adaptive software required to run it make this a task of herculean proportions. But the recent castings of the 15-metric ton, off-axis mirrors for the Giant Magellan Telescope forced engineers to push the design and manufacturing process beyond all previous limits.

Will be fun to see the Moon and it's craters in it! (o:


"Nanometer precision of its curves?" Really? The curves are accurate to one billionth of a meter??


The surface is finished to an accuracy of 20 nm. I don't think it's
unreasonable to characterize that as "nanometer precision".


Impressive, if true. What wavefront would that equal?