This is an enormously versatile Barlow lens system which can be used both visually and photographically. With additional adapters, variable amounts of extension are possible.
The Barlow consists of seven individual parts that guarantee optimal versatility. You can use it to fully illuminate 35 mm format cameras, integrate an optional star diagonal or amici prism or convert the Barlow into a world-class projection system for planetary/lunar photography with just a few accessories. 2" and 1.25" eyepiece filters can be used as well.
|Increase in focal length
|Focal length reduction
|Inner diameter (clear aperture)
|Inner connection (telescope side)
||M28 thread, T2 thread (M42 x 0.75)|
|Outer connection (telescope side)||1.25" barrel, 2" barrel|
|Inner connection (eyepiece side)||1.25" receptacle|
|Outer connection (eyepiece side)||T2 thread (M42 x 0.75)|
In its basic configuration, the Barlow lens is ready for connection to 1.25" focusers and accepts 1.25" eyepieces.
If you have no problem with parts protruding into the drawer, for example when using refractors, the Barlow lens can simply be inserted into a 2" focuser, the reducer # 15 then serves as a 2" barrel.
Without thread protection ring, the reducer provides a T2 connection for cameras.
If you remove the reducer # 15 from the basic configuration, you can screw the Barlow into the filter thread of a 2" eyepiece; if you leave out the adapter # 29 as well, you get back to T2 for cameras.
If you unscrew the two rings # 25A and the adapter # 29 from the basic configuration, you can screw the adapter # 14 with built-in Barlow element into the reducer # 15 and then insert the Barlow lens into 2" focusers without protruding far into it. Photographically, after removing the thread protection ring, the rings # 25A can then be screwed onto the T2 thread of the reducer # 15, giving more distance again.
If you put the linked adapter TST2-2 on the previous arrangement, you can use 2" eyepieces, alternatively you can use adapter # 29 if you want to use only one single eyepiece.