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Re: [tec-scopes] Re: Poll results for tec-scopes

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  • Chris Lord
    Andreas, I accept that and am well aware of it. However by judicious use aspheric surfaces it is theoretically possible to correct both at the same ray height.
    Message 1 of 59 , Aug 1, 2008
      Andreas,

      I accept that and am well aware of it. However by judicious use
      aspheric surfaces it is theoretically possible to correct both at the
      same ray height.

      The Abbe Orthoskop has a small fov so the residual rectilinear
      distortion is negligible. The definition of orthoscopy necessiates zero
      distortion (both types). It may not be possible to achieve it with
      spherical surfaces, but the definition requires the magnification to be
      uniform across the fov, and rectilinear objects to remain straight
      across the fov.

      The term originates in photography (Jozsef M. Petzval 1851) and an
      instrument called an Orthoscope ( an instrument containing a layer of
      water which is held in contact with the eye, allowing an examination of
      the interior of the eye without the distortion due to corneal
      refraction). A simple and sufficient definition of "orthoscopy" is that
      all points of the scene as viewed are at the same azimuth and altitude
      as they were in the original scene. This may only be achieved by
      correcting both types of distortion.

      I've not seem the Nagler Ethos, but I've been told it does not exhibit
      either distortion. I remain curious as to how it has been achieved.

      Chris Lord

      On Jul 31, 2008, at 21:33, Andreas Braun wrote:

      > Chris,
      >
      > with all due respect: it simply is impossible to correct an eyepiece
      > simultanously for rectilinear AND angular magnification distortion.
      > The first will satisfy the tan-formula and the latter the
      > arcus-formula. An orthoscopic design normally refers to "no - or very
      > little - rectilinear distortion".
      >
      > Andreas
    • tucstargzr
      Hi Mark, I have no concern with the technical side of the scope. Heck, LONG before this scope came up for sale I had read the manual and dreamed of owning it,
      Message 59 of 59 , Apr 6, 2009
        Hi Mark,

        I have no concern with the technical side of the scope. Heck, LONG before this scope came up for sale I had read the manual and dreamed of owning it, even placed a "WANTED" post here last summer.

        Yet my day job involves picking up on nits like this. Yuri said he'll check his manuals for current products and will improve them as necessary. Nothing more needs to be said or done.

        As for Chinese products in general...when I was a kid, MiJ was synonymous with junk, and now their products are highly desired. If China ever embraced Continuous Improvement in their products....

        http://www.youtube.com/watch?v=sHGNNaiLTQU&feature=related


        Bottom line? Teach your children. Encourage them to get as much education as possible.

        Tom
        Sings with the Stars


        --- In tec-scopes@yahoogroups.com, pandrolmb@... wrote:
        >
        > Tom,
        >
        > FTR: Legally speaking, government regulations require that a percentage of
        > components must be made in the US before a company can label "Made in USA."
        > The percentage varies according to industry exceptions too, but typically,
        > (assemblies) only need to have between 80% and 88% US made components to earn
        > the "made in USA" label. In many instances, certain components, and
        > especially when dealing with electronics are no longer manufactured in the USA at all!
        > That (forces) the US mfrs to go international for specific components. It
        > should also be noted that TEC has not only exceeded the percentage
        > requirement, by a long shot I might add, but neither of the components that you have
        > mentioned were provided by inexpensive sources like China, Indonesia, etc.
        > Instead, they were purchased from high-end manufacturers in countries that
        > typically charge even more than similar products manufactured in the USA. You
        > DID make it clear that you had no complaints about the scope, so hopefully,
        > this will help with technical reservations too ;-)
        >
        > STEADY skies!
        >
        > Mark
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