Re: [ATM] Optical flat etc, then what?

[DHA352@aol.com]

Thanks all 
Don
 
In a message dated 11/21/2004 7:01:49 PM Eastern Standard Time,  
srychnov@chem.ps.uci.edu writes:

Don,

For a nice discussion of the three mirror method, see  Thompson, "Make 
Your Own Telescope" p. 202.

For a discussion of  testing flats with a spherical method (Ritchey 
method) see Texereau p.  115-117.

For more discussion of these methods for testing, see  Mackintosh, 
"Advanced Telescope Making Techniques" Volume II, Chapter 6  (p. 
153-171).

Either the three mirror method or the Ritchey test  method could be used 
to make an excellent flat.  The Ritchey test  requires a good 
(preferably slow) spherical  mirror.

Scott


On Nov 21, 2004, at 2:36 PM, DHA352@aol.com  wrote:

> Okay I am convinced to test for flatness I need test plate  (optical 
> flat)
> that is flatter than my goal. The fringe lines  determine how flat my 
> work  is.
> I understand the three  work piece simultaneous equation method and its
> limits. Got that much,  now some more questions.
>
>> From fringe line  patterns:
> 1. How do I tell concave vs convex, or can  I?
>
> 2. What do I do about concave?
>
> 3. What do I  do about convex?
>
> 4. Chicken-and-the-egg question.  If I  need a 1/10delta flat to  test 
> for
> 1/4delta, a 1/20delta  to test for 1/10delta,...,etc. How is  the 
> flattest  optical
> flat tested?
>
> A reference to a book that would  address some of these questions would 
>  be
> much  appreciated.
>
> Thanks
> Don
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>
--
Scott Rychnovsky
ATM Web  page:
http://tlepage.home.mindspring.com/





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