Re: ATM Mirror Making Kit Proof Of Principle

[epabcc@epa.ericsson.se (Bratislav Curcic)]

Val,

great stuff ! This is what is really missing from todays leading
magazines. Instead articles on how to assemble telescope from
commercial parts, show how easy it is to get workable telescope OPTICS
by your own hands. I'm sure there would be lots of people trying to do
it just for a sheer thrill of making something with their own hands
(even if there is not much of a financial advantage to it).

Regarding steel rings for grinding - they should be used when there is
a significant amount of glass to be removed quickly (say f/5 and faster),
there won't be as much of an advantage for grinding an f/10 mirror ...
In theory, a steel ring of D/2 and greater will automatically produce a
perfect sphere (you can go all the way to fine grinding with it - in 
theory - I haven't tried it), but if you use smaller ring (in many cases 
more practical), surface may turn out to be non spherical, and it will need
some "mating". If you use tiles/plaster tool (cast on hogged out mirror), 
this doesn't matter, because you have to smooth the tool anyway, and by 
the time you've done this it will sphericize the mirror as well.

Bratislav