Re: [ATM] Building Foucault tester

[hermit <hermit@outofoptions.org>]

jeff newsom wrote:

>Howdy folks-
>   After sifting through numerous articles on the construction of a foucault tester, I came across one that suggested that a tester such as the Mir-O-Test had some inherent problems that limited it's accuracy, however, I can't remember the remedy. To build an accurate tester, what are some of the pitfalls one should avoid?
>   Thanks ---JN
>_______________________________________________
>  
>
This isn't complicated. 

You need a knife edge/razor blade.  You need a light source.  Easiest to 
put the light source behind the KE.  Then you can use a second KE to 
make a slit if you want.

Now you need a method of moving the KE 'in and out' from the mirror.  
You also need a way to measure how far it moves.  LOTS of configurations 
can be used.  Having a method of moving the KE side to side is very 
helpful also.  No need to measure this movement.

You can start with just the light source and KE to see the images on the 
mirror to get an idea.  It is much harder to set up without some sort of 
'fine control' though.  We are talking about moving this thing in the 
range of hundreths of an inch to see changes.

You may want to look up xy stages at places that sell machine tools.  
That may help you visualize what is needed.

Ken
_______________________________________________
ATM mailing list http://www.atmlist.net/