Re: ATM 10in. Mirror

[Len Lipton <llipton@erols.com>]

>absolute maddness to attempt a 10in. F/6 as a first attempt? My alternative
>

I've made 2 mirrors: a 4-1/4" f/8, and an 8" f/8, both under the guidance of
an instructor.  The 4-1/4" was very easy.  I could polish it with one hand,
parabolizing it took just a few strokes - and it taught me a lot.

The 8" was a bear - altogether about 200 hours of gringing, polishing and
figuring
(it did wind up at 1/10 wave p-v wavefront error according to the Foucault
readings).

After the small mirror I had the confidence to finish the larger one.  I
think you should start small - the second mirror will be easier.  The
traditional starter is a 6" f/8.  I chose a 4-1/4" to be even easier, plus
it made a nifty small scope.

- Regards, Len