[ATM] "Best" mirrot shape

[Peter De Baan De Baan]

Me thinks that I will close my eyes and see past infinety even without a telescope mirror 

 

Peter

 
> From: richard1941 at gmail.com
> To: wa4guu at verizon.net
> Date: Wed, 30 Sep 2009 14:26:47 -0700
> CC: atm at atmlist.net; almansor at dslextreme.com
> Subject: Re: [ATM] "Best" mirrot shape
> 
> It all depends (praphrasing president Clinton) which definition of 
> "best" is best. My definition was the smallest spot size over the 
> entire focal plane (usually 2" diameter).
> 
> Sent from Richard's iPhone
> 
> On Sep 29, 2009, at 13:43, "Jerry" <wa4guu at verizon.net> wrote:
> 
> > Hello Richard,
> >
> > I think that Hyperbolas are best single surface telescope for focusing
> > objects beyond infinity.
> >
> > The parabola is best for objects at infinity.
> >
> > An over-corrected ellipse (0 > b > -1) is the surface for things 
> > beyond the
> > center of curvature but less distant than infinity.
> >
> > All the astronomical objects that I have seen have been closer than
> > infinity. So that under-corrected ellipse is the one I would want 
> > for the
> > one surface telescope.
> >
> > Now it may be that atmospheric refraction might refract diverging or 
> > nearly
> > parallel rays to converging similar to rays coming from a point beyond
> > infinty. But in that case the atmosphere is one surface and the 
> > mirror is
> > the second.
> >
> > Maybe if we made a "perfect hyperbola" we could see other universes.
> >
> > Jerry
> >
> >
> > -----Original Message-----
> > From: richard schwartz
> >
> > And it may come as a shock to some that the best shape for a single 
> > mirror
> > telescope may actually be a hyperbola, not the standard parabola. 
> > (I was
> > amazed to find this by ray tracing a long time ago.)
> >
> > Now go figure... some more...
> >
> >
> >
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