Re: Off-Axis (Zero Obstruction) Reflector Telescopes

From: Ratboy99 (ratboy99_at_aol.comet)
Date: 10/04/04 

Date: 04 Oct 2004 20:58:12 GMT

>Good point. I could move the mask around and do tests so as
>to find the best section.
>

I doubt if you would be able to notice much real world difference by rotating
the mask, if I understand, most of the defects in a decent mirror are going to
be zonal.

Second, it is the outer edge of the mirror that generally carries the most
defects, so I'd positon your stop as close to the center as you can without
hitting the spider vanes.

Personally I think the idea of a 6.5" OA Newt is a good one for getting APO
performance for Newt price.

I've stopped my 18" Zambuto down to 6" good number of times, and while it does
work "as advertised", there is still the issue of pushing a 6" scope around
that "feels" like an 18"; a bit cumbersome for the effective aperture.

If I'm pushing around my ~100 lb 18" scope I prefer to be doing it for the 18"
worth of aperture, and I'm usually looking at DSO's with it then, anyway.
rat
~( );>

email: remove 'et' from .com(et) in above email address

Relevant Pages

  • Re: Off-Axis (Zero Obstruction) Reflector Telescopes
    ... I could move the mask around and do tests so as ... > the mask, if I understand, most of the defects in a decent mirror are going to ... > performance for Newt price. ... certainly less than a 6.5" APO! ...
    (sci.astro.amateur)
  • Re: Off-Axis (Zero Obstruction) Reflector Telescopes
    ... I could move the mask around and do tests so as ... > the mask, if I understand, most of the defects in a decent mirror are going to ... > performance for Newt price. ... which I understand gives true APO performance. ...
    (sci.astro.amateur)
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