Re: [ATM] Ball bearing for triangles

[Raphaël GUINAMARD <rguinamard@infonie.fr>]

Adrie,
I'll do testing in october because my secondary mirror has been returned to
an optician because it fell on my primary dust cover during transport and it
stripped...
Best regards
Raphaël Guinamard
----- Original Message ----- 
From: "A. Suijkerbuijk" <a.suykerbuyk@wxs.nl>
To: "Raphaël GUINAMARD" <rguinamard@infonie.fr>; <atm@atmlist.net>
Sent: Sunday, September 05, 2004 11:03 PM
Subject: Re: [ATM] Ball bearing for triangles


> Hi Rafaël,
>
> This certainly is a difficult mirror: thin and very short focus. It could
> even influence your eyepieces. Furthermore the star test is very critical,
a
> slight spherical aberration is easy to see......I am interested to hear
more
> about your experiments.
>
> Best regards,
> Adrie Suijkerbuijk.
>
> ----- Original Message ----- 
> From: "Raphaël GUINAMARD" <rguinamard@infonie.fr>
> To: <atm@atmlist.net>
> Sent: Sunday, September 05, 2004 8:00 PM
> Subject: Re: [ATM] Ball bearing for triangles
>
>
> >
> >
> > > Perhaps the mirror will reach the air temperature very fast, after
which
> > the
> > > aluminum side radiates most. In this case the mirror will cool below
the
> > air
> > > temperature?
> > it's exactly what I think
> >
> > >Or perhaps the meniscus plays a certain role.
> > In my case it is not a meniscus. It is a "classical" miror, but quite
thin
> > (40 mm) and with low focal ratio f/3.3=> 28-29 mm in the center. It's
the
> > thin thickness in the center and the big difference between thickness in
> the
> > center and at the edge that could cause the spherical aberation
> deformation.
> > In a thiker miror or bigger f/d it would certainly not occur.
> > But remember that at the moment it is only a theory for my mirror. I
have
> do
> > do some tests before being sure I have this problem
> > > About you mirror: You wrote that you see some spherical aberration in
> the
> > > star test. is it overcorrection or undercorrection?
> > If I remember correctly, it is overcorrected
> >
> > >I suppose this is after
> > > cooling?
> > yes...
> >
> >
> > _______________________________________________
> > ATM mailing list http://www.atmlist.net/
> >
>
>

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