Bob May Page So you really want to build a telescope mirror,here's another way to do the work along with some digressions on doing things related to making mirrors
David Harbour Understanding Foucault A Primer for Beginners
Interpretation of Ronchi Shadows
a small webpage showing various pictures of ronchi shadows and their corresponding surface defects.
Mike Lockwood's Mirror Making The advice given is intended to help those working on mirrors from 4" to 12" in diameter, with focal ratios between F/5 and F/8.