Hi Paul and Ed, and thanks for the warm welcomes.
My Foucault tester is a copy of the slitless Stellafane design:
http://stellafane.org/atm/atm_foucau...er_plans_1.htm
and has a moving light source. It's rough and ready but it works!
I have hogged and ground 8" and 12" blanks by hand but I am using a Mirror-o-Matic (
http://www.mirror-o-matic.com/) for this most recent effort. After hogging the 12 inch I got lazy. This mirror is the first I have got to final polishing stage.
I'm using 8" fine annealed Pyrex blanks that I was lucky enough to get from James Mulherin at Optical Mechanics in the US. James is a great guy and his work is first rate, as anyone lucky enough to have a recent Obsession dob might know.
My grand plan is to make a lightweight dob from laser-cut stainless, either a truss design or, if I get really ambitious, a string scope. Then I want to finish the 12" at F5 and maybe go onto an 8" binoscope or possible a more advanced optical design. But first things first!
Regards,
Justin