Re: [ATM] Fw: telescope

[Mark Holm <mdholm@telerama.com>]

David,

As Jerry has said, you probably have yet to realize just how big an 
enchilada you are trying to swallow.  The tough part of mirror making 
begins after you have it polished out.

There are particular methods you need to have in place to have a 
reasonable chance of success with such a thin mirror.  Mel Bartels has 
an on line article at  http://www.efn.org/~mbartels/tm/largthin.html
There is also an article in an appendix to the book "The Dobsonian 
Telescope" by David Kriege and Richard Berry.  I think Bob Kestner wrote 
that one.  You can order the book from Willman-Bell Publishing.  They 
have a web site.

I will recommend that you learn to do quantitative Foucault at least as 
a reality check on the matching Ronchi test.  There is software to help 
with Foucault data reduction.  Sixtests by Jim Burrows is my favorite.  
Google on Sixtests Burrows and you will get it.

The members of this list can give invaluable advice and you are very 
welcome to ask as many questions as you need.

Jerry asked a whole bunch, and even admitted publicly when he was 
discouraged to the point of giving up, but he stuck with it and the list 
members stuck with him.

Jerry mentioned the use of Plop to design a mirror cell.  You can 
certainly learn to use the program yourself, but there are several on 
the list with a fair amount of experience using it, and a few with quite 
a bit.  Don't be bashful about asking for help using Plop, or even to 
have someone else do the work and give you the results.  We do it all 
the time.  With that mirror, you will need a Plop designed cell to get 
good support.

Mark Holm
mdholm@telerama.aomc



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