RE: [ATM] Help needed with foucault

["Oliver Kersten" <oeli@comesso.de>]

Hi Jeremy,

the pictures were taken with a Olympus C5060 digital camera with 3x optical
zoom and additional ~1.5x digital zoom. The cam allows to save custom settings
for all parameters you can choose, so I saved a "foucault mode" that makes
setting up the test and adjusting the camera a lot easier and faster.

Greetings and thanks for your advice (to all),
  Oliver

Royston_Jeremy@emc.com:
> Hello Oliver,
> 	The mirror has a slight turned down edge a few mm wide. The bright
> rim is normal - the edge of the mirror behaves optically like a big scratch.
> Try hanging a wire abour 0.5mm diameter close to the mirror across the
> diameter, then look at the Foucault test - you'll see a bright line - this
> is the light diffracted round the wire.
> You have a few schlieren in the glass
> How did you make the pictures?
>
> Best wishes, Jerry
>
>
> -----Original Message-----
> From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net] On Behalf Of
> Oliver Kersten
> Sent: Donnerstag, 14. April 2005 01:05
> To: atm@atmlist.net
> Subject: [ATM] Help needed with foucault
>
> Hi all,
>
> after polishing my 10" F5.6 mirror for hours and hours (still heading for a
> sphere), I'm currently not sure if I see a strong TDE in foucault images, or
> just reflections of the mirror's
> edge. Maybe some of the experienced testers can have a look at the URL
> below, where I put four images taken at ROC, +2, +4 and +6mm (~100 KB each).
> What do you think? What should be the
> next polishing actions? After making short strokes with little overhang
> there seems to be a central hill, the edge didn't change much.
>
> -> http://www.comesso.de/oeli/foucault/foucault.html
>
> Greetings, Oliver
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>

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