[photo-3d] help ID an unusual old viewer?

[Peter Abrahams <telscope@xxxxxxxxxx>]

There is an intriguing binocular viewer for sale; I have no connection with
the owner & will not likely purchase it, however I am fascinated by the
varieties of viewers -- this isn't an advertisement, but a request for
information.  I posted a 45 kb  jpg of this viewer at:
http://home.europa.com/~telscope/viewer.jpg
It is estimated to be late 19th century & British; of brass, 4 inches wide,
with two greenish glass right angle prisms whose angle to each other is
adjustable & fixable by the central mechanism.  It produces side-by-side
images which are reversed, i.e. left to right and right to left. In
addition the viewer reverses writing so that it runs backwards right to left. 
I don't find it in a look through Wing or T. Brown.  
Drouin, F. The Stereoscope and Stereoscopic Photography. London 1894 (Reel
3-d 1995); p35 shows a schematic of a Duboscq stereoscope for viewing large
prints that uses two Dove prisms; it looks like the right angle prisms in
this viewer are similarly arranged; and arranging two Dove prisms in this
way produces the effects noted above.
Can anyone confirm the use of this viewer?
It is expensive, though the craftsmanship seems superb. I think it would be
appropriate to mention the instrument dealer who is selling it: Ray
Giordano in Massachusetts <antiqsci@xxxxxxxxxxxxxxx> if interested (Catalog
32, #384).
thanks
Peter
_______________________________________
Peter Abrahams   telscope@xxxxxxxxxx   The history of the telescope & 
   the binocular:   http://www.europa.com/~telscope/binotele.htm

 

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