From: "Dave McCarter" 
To: "Vladimir Galogaza" ,
        "ATM" 
Reply-To: "Dave McCarter" 


>
> >(even Hubble - they did a Foucault test which said
> >the mirror was a chunk of junk - but the NASA managers didn't believe it).
>
> I will rephrase a little this sentence.
>
> Mirror was faulty but NASA&Perkin Elmer  managers were a chunk of junk
> unable to recognize/admit  what they should clearly saw.
>
> Vladimir.

Not so. Perkin Elmer did not use any form of Foucault test on the Hubble mirror, as
they were using a much more sensitive interferometric test that gave them absolutely
total confidence in the surface they prepared. Unfortunately they were using the same
set up they had developed for the KH11 Keyhole Spy satellites, which use
not parabolic mirrors, but slightly elliptical mirrors. After the error was
discovered by
star testing, another test most good ATMs use before coating and certainly before
"flying" their scopes, PE put out the story that a small washer
misplaced the reference element in their test set up, hence the error. NOT!
Don't believe it for a
second!

Had they done a Foucault test they would indeed have noticed the error. But they had
misplaced confidence in their high tech solution. As someone on this list is fond of
saying, always question "conventional wisdom", for therein lies
folly and error.

Dave

--- BBBS/NT v4.00 MP