What is the primary use for the Baader UFC S70 40mm Extension?
Its primary use is to add exactly 40mm of rigid spacing to a Baader UFC imaging train. This is often necessary to achieve the specific back focus distance required by a focal reducer or field flattener, especially when other accessories like an off-axis guider are also in the light path.
How does the UFC S70 40mm Extension attach to other components?
The extension uses the Baader S70 dovetail system. One side features a male S70 dovetail, while the other has a female S70 dovetail clamp with locking screws. This design provides a secure, tilt-free connection that is superior to simple threaded adapters.
Will the Baader UFC S70 40mm Extension help me reach the 146mm back focus for my EdgeHD 0.7x reducer?
Yes, absolutely. The 40mm extension is an excellent component for building long back-focus trains like the one needed for an EdgeHD reducer. You would combine it with the UFC base, your camera-side UFC adapter, and other UFC spacers to precisely meet the 146mm requirement without flexure.
Can I use the UFC S70 40mm Extension with a Newtonian coma corrector requiring 55mm of back focus?
Using the 40mm extension alone would leave you with only 15mm for your camera adapter, which is often insufficient for a typical DSLR or astronomy camera. However, if your imaging train also includes a UFC filter slider or OAG which consumes additional back focus, the 40mm extension could be part of a valid 55mm solution. You must measure the path length of all components carefully.
Why should I use the Baader S70 40mm Extension instead of stacking smaller spacers?
A single, solid 40mm extension provides a more rigid and stable connection than stacking multiple shorter extensions. Each additional connection point is a potential source of tilt or flex. For critical imaging, a single piece is always preferable for maintaining optical alignment.
Does the Baader UFC S70 40mm Extension cause vignetting with a full-frame sensor?
The Baader S70 system is engineered with a large clear aperture specifically to prevent vignetting on sensors up to full-frame (35mm format). As a straight-through spacer, this 40mm extension maintains that clear aperture and will not introduce vignetting.
