Re: [ATM] Maksutov Corrector Cell Design

[Ken Hunter <atm_ken_hunter@yahoo.com>]

Yes, I agree with Bill here. 

The 13 inch Mak I made at Kitt Peak back in the 70's
had a fixed corrector cell. Much time was spent making
the corrector surfaces spherical and keeping the wedge
at an absolute minimum. It's true that if you look at
the corrector (highly tilted) it will look like an
elipse but if you are setting your corrector at this
much of an angle, you should be making shoes not
optics. 

As for the color induced by tilting the corrector...
Again, you are not going to see color from tilt if you
make the cell square to the tube. It does take quite a
lot of tilt to introduce any noticeable color into the
system and this much tilt would be easily visible from
quite a distance. Not something a careful worker would
do.

One of the nice things about the Mak design is the
spherical shapes on the corrector that negates the
need for alignment of the element.

See the Willmann-Bell books "Advanced Techniques..."
by Alan Mackintosh for reprints of the most important
Maksutov Circular articles and gleanings. Highly
recommended for all ATM's as it has lots of ideas and
information pertaining to most advanced telescope
designs though originally started for Mak enthusiasts.

Ken Hunter


--- Bill Marriott <bmarriott@pacbell.net> wrote:

> Hello:
> 
> I believe the importance in aligning the corrector
> in a Maksutov, has to 
> do with the corrector sitting square to the optical
> axis of the 
> telescope, in that any tilting from this alignment 
> will start to 
> introduce a prismatic affect, ie color.  Same for
> wedge between the two 
> surfaces, I believe.  When fabricating the OTA for
> my 6" Maknewt, I had 
> the ends of the tube cut square to its rotating
> lengthwise axis (big 
> lathe) and the corrector cell was also cut square,
> no adjustments (there 
> is in the mirror cell), and a very thin layer of
> automotive gasket paper 
> material was used to 'cushion' the aluminum-glass
> interface.  When 
> autocollimating the scope, I put the test flat right
> up against the 
> front of the cell, and it was very easy to find the
> image in the ronchi 
> tester.
> 
> Bill Marriott
> 
> Richard F.L.R. Snashall wrote:
> 
> >
> >
> > Gregg Swanson wrote:
> >
> >> What is CoC?
> >
> >
> > Center of Curvature (in this case)
> >
> >
> >
> 
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 


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