All the F words .. gotchu ;) I got to crash :/ I'll be offline for few days but I'll check in next week and catch up with you :) I know you don't celebrate Christmas.... but hopefully you get some time off cos off. Happy holidays, talk soon :)
An optical flat is a precisely polished flat surface, used as a reference against which the flatness of an unknown surface may be compared. It can measure the flatness of a surface in millionths of an inch.
Yes, it is. I've done it myself ... created and checked surfaces that were flat with .00005 (50 millionths of an inch). To give you an idea of just how big that is: The average human hair is .003 in diameter(3 thousandths of an inch). Now cut that hair into 60 equal pieces and you'll have a rough idea of how big .00005 is.