Re: [ATM] LWT setup questions

[Bernard Maugoust <maugoust@free.fr>]

Hi John,

In message <200505191953.AA171114726@mail.johnspics.com>, 
 "john sherman" <atm@mail.johnspics.com> wrote:

> On my old 22" I had a hard time with the Couder mask, judging those funny
> shadows. A cheapie LWT tester gave me reasonably repeatable results, it is
> the only method I know which would give me the confidence to figure with
> (James Burrows' new 2D Hartmann test looks pretty good. I've been wanting
> to try it out, and see how much confidence it gives me). Long ago I tried
> figuring an 8" with the Couder test and got nowhere. If it was the only
> thing available, I would never make a mirror.

Bit tough on the Couder mask that... The 8" I'll try to 'finish' once for
good is already reasonably figured just with that method. Plus, we now have
the right software to come out with glass profiles in matter of seconds,
while back then I'd reduce the data with my HP pocket calculator...
 
> What part of the spot test gave you a problem? 

The pinhole! I never managed to devote enough care to come up with a clean,
perfectly round and tiny thing. Give me whatever name you like!
 
> Have fun,

I will ;-)

Regards,

Bernard

-- 
Bernard Maugoust 3°59'E 44°28'N

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