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Re: Is Glass a Liquid?

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On 10/2/2015 1:55 AM, Angelo wrote:
> Il giorno venerdì 2 ottobre 2015 07:39:05 UTC+2, pnal...@gmail.com ha
> scritto:
>> On Thursday, October 1, 2015 at 8:01:39 PM UTC-7, benj wrote:
>>

> A large lens in a refracting telescope offers a much more sensitive
> probe: "In very large apertures, there is also a problem of lens
> sagging, a result of gravity deforming glass. Since a lens can only
> be held in place by its edge, the center of a large lens sags due to
> gravity, distorting the images it produces. The largest practical
> lens size in a refracting telescope is around 1 meter (39 in)."
> https://en.wikipedia.org/wiki/Refracting_telescope#Technical_considerations
>
>  Perhaps this fact contributed in part to the abandonment of large
> refractors (gravity deforming lenses).
>

but that is not flow.  that is just sag,

the mounts sag too, and they are steel.

large refractors cost to much to build the lens, and have a chance it
will fracture.

Refractors you can spin in an oven and get the surface close, cheaper

you still have sag problems with the large refractors



> regards Angelo
>

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Thread

Is Glass a Liquid? Sam Wormley <swormley1@gmail.com> - 2015-10-01 19:11 -0500
  no, and yes noTthaTguY <abu.kuanysh05@gmail.com> - 2015-10-01 18:28 -0700
  Re: Is Glass a Liquid? jimp@specsol.spam.sux.com - 2015-10-02 01:19 +0000
  Re: Is Glass a Liquid? benj <nobody@gmail.com> - 2015-10-01 23:01 -0400
    Re: Is Glass a Liquid? pnalsing@gmail.com - 2015-10-01 22:38 -0700
      Re: Is Glass a Liquid? Angelo <patrizio.pan-2002@libero.it> - 2015-10-01 23:55 -0700
        Re: Is Glass a Liquid? john <johnsefton288@gmail.com> - 2015-10-02 06:33 -0700
          Re: Is Glass a Liquid? Angelo <patrizio.pan-2002@libero.it> - 2015-10-02 07:14 -0700
        Re: Is Glass a Liquid? benj <nobody@gmail.com> - 2015-10-02 12:19 -0400
          Re: Is Glass a Liquid? Mahipal <mahipal7638@gmail.com> - 2015-10-02 15:43 -0700
            Re: Is Glass a Liquid? "Le Nymster" <invalid@example.com> - 2015-10-02 19:05 -0700
          Re: Is Glass a Liquid? Angelo <patrizio.pan-2002@libero.it> - 2015-10-02 19:41 -0700
            Re: Is Glass a Liquid? benj <nobody@gmail.com> - 2015-10-03 03:05 -0400
        Re: Is Glass a Liquid? gilber34 <fafa@invalid.com> - 2015-10-02 17:07 -0500
          Re: Is Glass a Liquid? Angelo <patrizio.pan-2002@libero.it> - 2015-10-02 16:56 -0700
  Re: Is Glass a Liquid? Helmut Wabnig <hwabnig@.- --- -.dotat> - 2015-10-02 08:34 +0200
  Re: Is Glass a Liquid? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-10-02 10:48 -0700
  Re: Is Glass a Liquid? Double-A <double-a3@hush.com> - 2015-10-02 13:25 -0700
    Re: Is Glass a Liquid? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-10-02 15:27 -0700
  Re: Is Glass a Liquid? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-10-02 13:30 -0700
    Re: Is Glass a Liquid? Double-A <double-a3@hush.com> - 2015-10-02 14:31 -0700
    Re: Is Glass a Liquid? benj <nobody@gmail.com> - 2015-10-03 03:19 -0400
      Re: Is Glass a Liquid? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-10-03 10:12 -0700
        Re: Is Glass a Liquid? "hanson" <hanson@quick.net> - 2015-10-03 21:17 -0700
  Re: Is Glass a Liquid? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-10-02 14:43 -0700

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