Lacerta 2.6x Lightpath Corrector (Barlow)
This Light-path Corrector works similarly to Barlow lenses but the main aim of its use is for example to reduce the optical path of a binoviewer (William Optics binoviewer) when focus cannot be achieved with the original factory setup.
E.g. the William Optics (WO) binoviewer has 105mm optical path, with the originally supplied 1.6x Barlow/Light-path Corrector this can be reduced to 47mm, but in many cases (many Newtonian reflectors) this will still be too long.
The 2.6x Barlow/Light-path Corrector will reduce it to 8mm thus focus can be easily achived with any Newtonian reflector.
How it works: simply screw it in into the 28.5mm thread of the binoviewer at its lower end.
Please note that optically it's impossible to achieve the above without some vignetting.