2 eye viewing of single eyepiece FOV

[25585]

While bino viewers allow 2 eye viewing, an eye piece is needed for each eye, and limited to 1.25 inch diameter lenses. 

Are there any optics, or set-ups which would allow 2 eye viewing using a single eye piece, apart from digi-viewing?

Would, for example, a bino viewer attached to a wide field eye piece, and the necessary extensions, work? Only needing sufficient eye lenses to allow enough magnification and dioptric adjustments etc. 

It would be great to be able to see the whole FOV, with both eyes together, from an 80+ degree, 2+ inch diameter eye piece!

 

 

 

[Geoff Lister]

As a quick thought, if the splitter were on the observer's side of a single EP, it would be in the eye relief zone of the EP. Challenging if the light path were over 15mm.

With my binoviewer, I use the 10mm & 25mm EPs supplied with my various Synta 'scopes. The non-Maks require a x2 Barlow to achieve focus, so equivalent to 5mm & 12.5mm. I have recently bought a pair of 7-21mm zooms (about £40 each) and hope to give these a try soon.

[25585]

I have 6 pairs of eps for bv, but the largest AFOV is 65 deg. 

I need usable eye relief of at least 20mm. Obviously width of ep in a bv is a big factor. 8mm Vixen LVW is the widest for my eye spacing & nose accommodation. 

Which is why a single UWA ep view seen with both eyes is appealing. There are some 35mm camera bodies which have a waist level viewer that can be swapped with a prism - usually professional models. But maybe a Baader T2 diagonal could be used instead, although vignetting, which would defeat the purpose. 

WRT light path & projection etc, are there any T2 extension tubes that are helical or push-pull for varying length?

[Moonshane]

Easier to buy a scope with a shorter focal length surely?