Null test lens for a 30" F/4 mirror?

What size, quality, and specific type of lens would be required to use a
Foucault tester as a Ross Null Tester for a 30" ~f/4 mirror? Does anyone
make such a beast?

Lawrence Sayre
--
------------------------------------------------------------------------
My philosophy, in essence, is the concept of man as
a moral being, with his own happiness as the moral
purpose of his life, with productive achievement as
his noblest activity, and reason as his only absolute.

Ayn Rand (in the appendix to 'Atlas Shrugged')
------------------------------------------------------------------------

Lawrence Sayre wrote:

What size, quality, and specific type of lens would be required to
use a Foucault tester as a Ross Null Tester for a 30" ~f/4 mirror?
Does anyone make such a beast?

You may find there are multiple answers to this question. For example
(if you
have OSLO available to you):

http://users.rcn.com/rflrs/Ross_Test.len


Lawrence Sayre


--

Rick S.

http://users.rcn.com/rflrs



--

Rick S.

http://users.rcn.com/rflrs

On Thu, 04 Mar 2004 04:13:37 +0000, Richard F.L.R. Snashall
wrote:



Lawrence Sayre wrote:

What size, quality, and specific type of lens would be required to use
a Foucault tester as a Ross Null Tester for a 30" ~f/4 mirror? Does
anyone make such a beast?

You may find there are multiple answers to this question. For example
(if you
have OSLO available to you):

http://users.rcn.com/rflrs/Ross_Test.len


Lawrence Sayre



Sorry, but I'm exclusively a Linux OS person. Can't run most Windows
stuff.

Lawrence Sayre
--
------------------------------------------------------------------------
My philosophy, in essence, is the concept of man as
a moral being, with his own happiness as the moral
purpose of his life, with productive achievement as
his noblest activity, and reason as his only absolute.

Ayn Rand (in the appendix to 'Atlas Shrugged')
------------------------------------------------------------------------

Lawrence Sayre wrote:

On Thu, 04 Mar 2004 04:13:37 +0000, Richard F.L.R. Snashall
wrote:



Lawrence Sayre wrote:

What size, quality, and specific type of lens would be required to
use a Foucault tester as a Ross Null Tester for a 30" ~f/4
mirror? Does anyone make such a beast?


You may find there are multiple answers to this question. For
example (if you
have OSLO available to you):

http://users.rcn.com/rflrs/Ross_Test.len


Lawrence Sayre




Sorry, but I'm exclusively a Linux OS person. Can't run most Windows
stuff.


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The size of the lens is about half the size of the mirror
(in this case, the mirror was 8" and the lens was 100 mm).


Lawrence Sayre


--

Rick S.

http://users.rcn.com/rflrs