Our totally new photo-visual apochromatic Barlow with real ED glass, calculated for the correction of Off-Axis Coma at Newtonian telescopes. This Barlow allows you to observe planets and deep sky objects at the edge from the 1.25" field of view with the same quality as on axis. Especially Dobsonian user will profit because most time the objects are not exactly centered on axis.
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