Re: Star Test Question

Jan R. Sugalski (afn19866@freenet.ufl.edu)
Mon, 1 May 1995 20:17:54 -0400 (EDT)

To all glass pushers: I would never suggest the Ronchi test for everything and I don't know who would. However, there is no way the star test is a better indicator of zones than the Foucault or Ronchi test when properly used. By the way. If you want a good education in figuring I recommend making three 8" optical flats by the three disk method to 1/10 wave. If you live thru it, you will have some very useful items. Keep one and sell the other two. Jan

On Mon, 1 May 1995, Mark VandeWettering wrote:

> Date: Mon, 1 May 1995 08:01:07 -0700
> From: Mark VandeWettering <markv@tick>
> To: atm@best.com
> Subject: Re: Star Test Question
>
> I disagree for a couple of reasons:
> 1. Star testing is actually pretty simple, and Dick Suiter's book
> has made it even simpler.
> 2. Star testing is the only way for the average amateur to test
> the ENTIRE TELESCOPE. Ronchi testing at the ROC won't cut it.
> For newtonians, it doesn't tell you a thing about your diagonal.
> 3. Sure, autocollimation is good, but even I don't have a good flat,
> and I am obsessed by telescope making. :) Also for large mirrors
> this becomes more expensive.
> That aside, I think the best method is to use ALL methods, and try to
> figure out what each is telling you about your mirror.
>
> Mark
>
> --
> Mark T. VandeWettering Telescope Information (and
>more)
> Email: <markv@pixar.com> http://webspace.com/markv/
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