My guess is the purists would say it's off topic but I figure it's as right as talking about the focault test.
I bought the book shortly after it came out and am very pleased with it. Now all I need is some skies to do some testing! Cloudy since a week ago Friday and more in the picture :(
It is a wonderful book that really expands on the short articles that have been printed in the astro mags. If I get a good enough night I figure I could actually tell how undercorrected my mirror is. He talks of obstructions, polish, turned edges, zones and more that can be seen with the test. Like observing galaxies, planets, etc I think one would get much better with time and pratice and do quite a good evaluation of an optic system .
Ken