Hey thanks Dave! a 10" f/4 would be hard work! Did you get a great figure in the end?
I will try a full size lap first and see how it goes..
Knocked the TDE off last night and have now got very close to a sphere. Just have a slight depression in the centre. As a rough guess I have a 1/6-1/8 wave sphere.
Might try a 20min session at parabolising and then test. I think the slight hole in the centre will work in my favor!
I shall start a new thread about this and my progress!
cheers Gary