Lacerta 3.0x 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 3.0x Barlow/Light-path Corrector will reduce the optical path to practically zero, so focus can be easily achived with any Newtonian reflector. Please note, with this strong barlowing effect we have the largest optical distorsion as well, so go for this only if you need lots of back focus for your binoviewer kit.
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.