From: Jon Bishop 
To: John Murray 
Cc: Amateur Telescope Makers 
Reply-To: Jon Bishop 


But if you are using the knife edge test then doesn't the knive edge need
to be in the path of the returning rays?

Jon

> G'day John,
>     I use a JVC digital camera with auto focus, auto exposure to take my
> foucault and ronchi pics. There's no black art to it. Just have the camera
> supported in one spot so it doesn't move and then adjust the tester to feed
> the return beam into the lens. See my page on ronchigrams in my sig to see
> the results..
>
> Cheers
>
> John Murray
> Whyalla
> South Australia
> Check our web page at http://astronomy.sa86net.com ATM and M-O-M stuff.
> Latest Ronchigrams only at http://www.users.bigpond.com/imasloth/
>
> -----Original Message-----
> From: owner-atm{at}shore.net [mailto:owner-atm{at}shore.net]On Behalf Of Jon
> Bishop
> Sent: Friday, 15 August 2003 9:11 AM
> To: ATM
> Subject: ATM Foucaul pictures using digital camera.
>
> Hi,
> I am in the process of polishing and figuring an 8" F5.25 mirror. I would
> like some advice on figuring it, but before I do that it would be nice to
> take some pictures of the mirror under test.
> I have a Canon A40 digital camera, but when I try to use it it does not pick
> up the mirror disk. Has anyone suceeded in using an autofocus digital camera
> to do this?
> Thanks,

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