There are eyepieces which already have a built-in kind of barlow element inside of the 1.25" barrel, here you can't insert the Q-Barlow.
Baader Planetarium Q-Barlow 2,25x / 1,3xWithout the housing, the Barlow lens can be screwed either into the eyepiece revolver (for 2.25x magnification) or directly into an eyepiece (for 1.3x magnification)The Q-Barlow lens can be unscrewed from the eyepiece adapter
This high-quality 2.25x Barlow made of exotic glasses provides the rare extension factor of 2.25x. So, there are no duplicate focal lengths when used with the eyepieces of the Q-Turret Set, and you can achieve higher magnification than with standard 2x barlow lenses if you do planetary photography with a web or video camera, and you can make better use of the camera's resolution. Read here the detailed report by Dipl.-Ing W. Paech: Hints + tricks for high-resolution lunar and planetary photography with a video module - a short "workflow" for SC telescopes with Baader accessories.
The Barlow can either be screwed into the Q-Turret eyepiece turret or combined via the special, included adapter with all 1.25 "eyepieces. In this case, it acts as a 2.25x Barlow. With the Q-turret revolver and the Classic Eyepieces, this results in the following focal lengths: 2.7 mm, 4.5 mm, 8 mm and 14 mm
Alternatively, it can also be screwed directly into an eyepiece and then increases the telescope focal length by a factor of 1.3. The Barlow element has an M28.5 male thread (corresponding to the filter thread of 1¼ "eyepieces), the housing has got a M28.5- female thread.
|Inner Connection (lens sided)||Thread, M28,5|
|Outer Connection (lens sided)||Barrel, 1¼"|
|Outer Connection (eyepiece/-camera-sided)||Clamp, 1¼"|
|Clamping System||Screw clamps|
|Magnification (x)||2,25x / 1,3x|
|AR-Coating||High transmission multi-coated (HT-MC)|
|Adaptable to||Q-Turret Okularrevolver und Classic Ortho/Plössl Okulare, 1¼ Okulare|
|Usage||Erweitert die möglichen Brennweiten des Q-Turret Okularsatzes.|
|Barrel Size (in)||1¼"|