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Archives of an email list on the history of binoculars. - page 134 / 150

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War production: 620,000 binoculars; 23,812 rangefinders; 394,463 telescopes.  

New design by R.G. Budden of Admiralty Research Lab, 5x40 binocular, fixed focus or focus by longitudinal movement of prisms.  

Total destruction of R. & J. Beck factory at Clerkenwell, where were manufactured artillery dial sights, which aim to the side or rear of a hidden target.

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Subject: Monocular 'golf scopes'

From: gordiray@___t

I urge all to get the 5 x20 golf scopes now closing out.  Google "golf scope".  If only to check diopter settings.  Added to a comparator, one can quantitatively measure collimation error and relative image rotation. Ignore the "yards".  Measure the reticle by looking backward at it with a military binoc with a mil scale, or similar military sight or surveying instrument.  Then convert to degrees, or grads, or radians or what you will .  To see why this works, sketch  a ray from the edge of the reticle, through the center of the golf scope objective ( an undeviated chief ray, in optical design terminology, but you do not need to know that for this purpose).    These can work as sights, auxiliary telescopes, etc.  Image is erect.  All that for about $5-$10.  You can see if things were damaged in transit down a mountain, during a Border Patrol chase, or if they left the Chinese factory within civilized tolerances, which, if recent visits to sporting goods chain outlets and marine suppliers,  and gun shows, is doubtful, if you add it to a JTII  hand collimator, our build an easy Army-Henson setup.  All that is needed for this is the golf scope and a way to slide it.  Henson-Army used a machinist`s surface gauge with pins out, the pins sliding on a  flat surface with flat edge :  a countertop cutout might suffice.  I used a setup like this for many years.  Alone , it is not suited to get  hinge axes parallel to optical axes, but is good as an error measurer.

Gordon Rayner

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Subject: Rangefinder

From: Peter Abrahams

Someone in Katoomba Australia got hold of a big battleship rangefinder & set it up for public use as 'the world's largest privately owned telescope'.  A postcard was recently sold on ebay (not to me); but I saved the image & posted it:

http://home.europa.com/~telscope/temp/rangefinder.Katoomba.NSW.Australia.dup.jpg

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Subject: Another big reflecting bino telescope

From: "Gene A. Lucas" <geneluca@___com.com>

Here is a link to a very large (510mm, or 20 inch aperture) reflecting binocular telescope.

http://deepsky.cia.com.au/binoculars/clive/510mm_binoculars.html

Of course, many similar binocular telescope projects come to light from time to time, including some with motorized chairs to carry the observer....Is there interest on the Bino List about these projects?  A member of my other club (Saguaro Astronomy Club, SAC), Steve Dodder, is restoring the 8 inch (203 mm) f:5 binocular observing chair constructed by the late Pierre Schwaar.  Here are some links:

Steve Dodder's pages

http://www.stargazing.net/Astroman/contents.html

Schwaar Bino Chair restoration project:

http://www.stargazing.net/astroman/atm/binocularchair.html

Pierre observing with the 8 inch bino chair at RTMC 1991:

http://www.rtmcastronomyexpo.org/archives/photos/91RTMC06.jpg

http://www.rtmcastronomyexpo.org/archives/photos/91RTMC07.jpg

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