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The long-awaited conversion to CN 3.0 is in progress. Please see this thread for important information.

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Older commercial 100mm bino layout
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Poster: GlennLeDrew (see all of this user's photos)
Description: An older commercial 100mm binocular design. Because of the f/3.5 objectives, the effective aperture is less than 90mm when any standard Porro prism is used. (By 'standard' I mean that both prisms in each Porro pair are of the same size, i.e., the first prism is not of the tapered or stepped form.)

Tony Mach

Registered: 10/22/2013
Posts: 1
I was wondering: What software did you use to calculate this? I currently use a spread-sheet to calculate things like effective aperture, but I think if I had a dedicated software for this, then this might be helpful!
Thu Oct 31, 2013 3:16am
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Registered: 6/18/2008
Posts: 10249
I'm not sure of the wisdom of including hyperlinks here. Google "Sky and Telescope LeDrew freeware"; you can download the software I wrote (back in 2002) to do this. It runs in a DOS session, and hopefully is fine with the latest Windows OS's.
Fri Nov 1, 2013 5:20am
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