Re: ATM Sub-diameter tools?

[Brent Russell <brussel@global.co.za>]

Hi Mike

The other thing I should warn you about is that using TOT I seem to
always come out with an oblate spheriod that can be a pain in the butt
to make into a parabola on a larger and faster mirror. I would suggest
that you polish TOT until the edge looks perfect and then do some MOT
again to help bring you back to a sphere.

With my 7" that I refigured I used a hard pitch (the weather was cold)
and I hd a wonderfull oblate spheroid. By using standard parabolizing
strokes to deepen the center I kept the edge perfect. Howver with a
larger mirror and faster f ratio, you will have to do more
parabolization on the outer zones which, for me, meant a bad edge on my
12" (only the outer 2/3mm)

Cheers

Brent