We start with an 8" astronomical mirror - figured to within 1/8th wave surface accuracy:

A. Wavelength of green light: 550NM (0.00000055 Meters)

B. Convert this to inches (x's 39.37): 0.00002165"

C. 1/8th of the above would be 0.0000027"

*So - just how smoooooth is 2.7 millionths of an Inch?*

If we were to expand the diameter of our 8" mirror to One Mile - its (6 to 1 ratio) edge would stand almost 300 yards tall - and its finished face would have a surface accuracy of approximately 1/50th of an inch.

Folks, is that a reasonable approximation of reality?