It's almost certainly all about the pattern. I make telescope mirrors. The error... | Hacker News

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		Florin_Andrei on Jan 14, 2014 \| parent \| context \| favorite \| on: Fingers can detect nano-scale wrinkles even on a s... It's almost certainly all about the pattern. I make telescope mirrors. The error I'm allowed is 100 nm. I would love to just drag my fingers over the glass and tell if something is not quite right with the optical surface. In reality, I need a pretty elaborate optical setup to amplify the errors about 1/2 million times, in order to see them. I'm guessing the spatial frequency of the pattern in that experiment is on the same size scale like the vertical amplitude of it.

taavi013 on Jan 14, 2014 [–]

It is rumoured that Bernhard Schmidt had so sensitive touch, that he could physically feel polishing results by his (only) left hand.

http://en.wikipedia.org/wiki/Bernhard_Schmidt#Mittweida_year...

Florin_Andrei on Jan 15, 2014 | [–]

If this is about the early stages of polishing, I believe it (and I can do it myself).

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