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Binoviewer architecture

Started by yahganlang, 04/07/2006 01:05PM
Posted 04/07/2006 01:05PM Opening Post
Hi. I've seen two types of binoviewers- one is the type like a binocular with a center column that lets you rotate the tubes for IPD adjustment, without it changing the length of the light paths. The other, which I've only seen with older microscope binoviewers (do they still make these?) has a fixed body and IPD is done by lateral slide focusing which also means the ep's must rise and fall to compensate for change in light path length.

Are there any advantages or disadvantages of one type over the other? I myself prefer the second, fixed-body type, and have wondered why they don't make them for telescopes. In addition, a variation of the theme might be great for binoscopes proper, if the prisms or mirrors are turned 180 and no beamsplitter. Reverse binoculars already use something like this, but I was thinking refractors- all the designs people are discussing here (and elsewhere I've seen) for refractor binoscopes miss the fixed body idea.

Anyway, I'd like to hear thoughts on the above if any of you feel like chiming in. Thanks much.

Jess Tauber
Posted 04/07/2006 02:52PM #1
The fixed body type is a bit more complicaated, since
there is some internal gearing to keep the two
eyepieces equidistant from the beam splitter as
they slide. And of course the focus changes
as you adjust the inter-pupilary.

Also, the center-column type can use larger optics.
The beam splitter, etc., does not have to fit between
the inter-pupilary distance. But I'm not sure this
actually drives the choice; very few have optics
larger than half the inter-pupilary distance
(the design limit for fixed body types).