Glas FK61 (similar to Ohara FPL51), has blackenededges, a measured transmission von over 99% from 400 nm to 700 nm, optimized for F/4 Newtonian-Telescopes. The barlow has a negative focal length of - 62.9 mm and a working backfocuse of 105 mm from center last lens to focuse ( eyepiece field stop). You will need now a 1.25" eyepiece holer 104 mm long
This is a single tube, dual eye” one of the most popular night vision goggles in industry. Fully adjustable, padded headgear allows the device to be flipped-up or quickly detached from the mask. Optional 3X or 5X magnification multicoated lens will convert this device into a high performance long range binoculars. They’re lightweight, fully submersible, rugged, precisely built and easy to use. This model is able to accommodate both AA and CR123 batteries without any accessories.
Features:
Lightweight construction
High strength with metal fuselage
Three-light separation and optical design, digital image acquisition can be realized without affecting visual observation