Re: Re[2]: [ATM] On Axis Foucault (try this instead)

["David Harbour" <scarab2@cox.net>]

"KISS"

Need an explanation? Write and I will explain. 

Dave


----- Original Message ----- 
From: "Richard" <cnc@cncservo.co.uk>
To: "David Harbour" <scarab2@cox.net>
Cc: "ATM List" <atm@atmlist.net>; <aneves@snowsoft.biz>
Sent: Wednesday, June 15, 2005 10:26 AM
Subject: Re[2]: [ATM] On Axis Foucault (try this instead)


> Hi David,
> 
> Wednesday, June 15, 2005, 3:47:48 PM, you wrote:
> 
> DH> I and others (most notably John Sherman) have been preaching this for
> DH> decades; and yet we just can't
> DH> make it catch on.
> 
> Not sure what it is that we can't catch onto David, but maybe
> you can draw on your experience to help me please.
> 
> I have to test a 2" F/2 spherical mirror (yes, TWO inch).
> Actually it has focal length 100mm and usable diameter 50mm.
> Ideally I would like to get it to lambda/20 or as near to
> perfection as I can over the central 80%, as it will be the
> reference element in an interferometer and any error in it will
> cause errors in everything that is ever tested with the
> interferometer in the future.
> 
> Could you talk me through a layout for Focault testing it
> please?. Assume ignorance as I haven't done this for many years.
> Eg, I don't know what to use for an abberation free light
> source. What I do have, that I can pull off my microscope, is an
> X-Y table with 1um/0.0001" digital micrometers. Also have a
> laser, microscope objectives, smattering of lenses, LED's,
> pellicles, cube beamsplitters, digital camera, poor eyesight.
> 
> I'm happy to send it away to a calibration lab to assure it's
> final quality, but any help in achieving it would be much
> appreciated.
> 
> -- 
> 
> Best regards,
>   Richard in the UK
> 
> 
> 
> 

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