Looks like countries are the intuitive units to capture deviations at this level of scale. From NASA's web page about the mirrors in the James Webb telescope [0

Looks like countries are the intuitive units to capture deviations at this level of scale. From NASA's web page about the mirrors in the James Webb telescope [0]: "That means if the continental United States was polished smooth to the same tolerances, the entire country – from Maine to California – would not vary in thickness by just over two inches!" Given the US is roughly 27 times the area of Germany, looks like semiconductor manufacturing requires roughly double the accuracy of space telescopes (1 mm * 27 is slightly more than 1 inch) [0] https://www.nasa.gov/topics/technology/features/webb-craft.html https://www.nasa.gov/topics/technology/features/webb-craft.h...