TS binoviewer for backfocus lacking refractors ( and Newts)

[Bivanus]

Newbie question: would this type of bino-viewer be ok for general sky observation - a bit of DSO , a bit of planetary.I would like to 'take the plunge' but I find myself a tad reluctant due to the volume of ATM/DIY that seems involve outside of the few bino friendly OTA's.

It's interesting since the blurb says it's specifically designed for refractors (and Newts) that don't have a bino-friendly backfocus. Unfortunately, it also says if I understand correctly that wide-field EP's are a no-no due to a 17.3 mm field stop.

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p10297_TS-Optics-parfokaler-1-25---Binoansatz-1-1-Vergroe-erung---voller-Wegausgleich.html

[Highburymark]

This is a specialist binoviewer - primarily designed for those who can’t reach focus with traditional BVs. The complex optics aren’t quite up to the quality of simpler binoviewers, and yes, it only offers a relatively narrow field of view. Certainly not ideal for DSOs. I’d only recommend it if you can’t use other units. At that price you could possibly get a Baader Maxbright II - with nice wide views, and excellent quality. Or the cheaper Chinese BVs (WO, OVL, TS, Celestron etc) are pretty good - narrower prisms though.

[Bivanus]

Well, I finally did join the Dual Wielding Side of the Sforce , and in the most dastardly way posible it would seem : modified Leica microscope head with mirrors on 2" connection 🤣

Unsurprisingly , my OTA's only focused in straight thru view until I put toghether a poorman's GPC using a 1.25" to M48 filter adapter and a 2x Barlow lens cell.

Also a tad to learn on the eyepieces as Leica uses D30mm microscope ones, untill then i'l use the 16mm equivalent EP's that arrived with the bino ( modified Zeiss 8x30 Deltrintem) and 23mm aspherics for which I've manage to get some 30mm adapters made. A third pair of 32mm Plossls is in work , I have to find the second piece in the pair.

The moon looks magic through the Zeiss , full 3D magic and no CA and decent thru the aspherics ( you can see more of it with them too) 

[Louis D]

Among affordable eyepiece pairs with near max true field of view for affordable binoviewers, I've used the 23mm Aspherics with my Arcturus binoviewer (made by Norin Optech), but much prefer the Svbony 20mm 68 degree UWAs for their much better clarity, contrast, and sharpness.  They're best at f/12 and slower.  I use the optical nosepiece of a vintage Meade 140 2x Barlow to reach focus.  I just screw it into the insertion barrel of the BV.

[Bivanus]

@Louis D I have one 20mm 68deg from ES , was thinking to use it in a pair , sadly the lathe i've found only does 0.5/0.75/1mm thread steps and the ES has the standard 1.25" thread 27.5 x 0.6 so it'l have to wait.

Probably going to 'upgrade' the binoviewer to 1.25" holders in the future but currently I'm playing with it as it is - and use eyepieces that come with 0.75mm thread with adaptors.

EDIT: I was thinking at this type of adapters , iniatially wa looking at the click-lock but I did read that it sometimes does not hold the EP as intended and that the screw ones are safer. 

Edited April 24 by Bivanus
adapter pictures added

[Louis D]

The Arcturus ones are more or less self-centering.  The ones with thumbscrews can push eyepieces off-center making merging more difficult.

Baader Click-locks are not self-centering.  They actually push the eyepiece to one side.