Re: [ATM] 12.5 inches BVC advice for parabolizing

[Dale Eason <atmpob@yahoo.com>]

In a recent post you said you do not understand how to
do a knife test.  You will need to understand how to
do a Foucault test or else you will not know when to
stop or when to change stroke.

How are you judging when you will be done?  Ronchii
images will not help you at that point.  Suiter has
shown in his book that for fast mirrors like yours it
is impossible to tell a good figure from a 1/2 wave
one using only ronchi. In general they can only tell
you about the smoothness of the surface and edge.

Dale Eason

--- RM L <atm@axeinformatique.com> wrote:

> Hello again,
> 
> I'd love some advice as what approach to take when I
> continue the work, on another day. I do not want to
> mess up, and you may see allready a bad tendency in
> my images... that I wouldn't see.
> 
> I update my site with the last photos for the day.
> 
>
http://www.axeinformatique.com/temp/Mirror/BVC_Mirror.html
> 
> The zoning is allmost gone now. 
> 
> I'm using standard parabolizing W stroke, going up
> to 1,5 in of the border, with the center of mirror.
> 
> Should I keep doing the same thing ? It's the edge
> that scares me a little... Is it parabolizing
> quicker than the rest ? Am I worstening the TDE ?
> 
> I don't want to waste energy curing the TDE, but I
> would'nt want to make it worst.
> 
> Thanks all for your time, patience, and help.
> 
> 
> 
> 
> 
> 
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 


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