Baader T-2 Conversion Ring - 10mm T-2(F)/T-2(F)

Its primary use is to connect two accessories that both have male T-2 threads, while simultaneously adding exactly 10mm of spacing. This is most often required to achieve the precise back focus distance mandated by a field flattener or focal reducer for optimal performance.

In that scenario, you need to add a total of 37.5mm of spacing (55mm - 17.5mm) between your reducer and the camera's T-ring. The 10mm T-2 ring would be one component in that setup, likely combined with other Baader T-2 spacers (e.g., a 20mm tube and a 7.5mm ring) to precisely reach the required total distance.

Yes. The entire Baader Astro T-2 System is designed for modularity. You can stack multiple fixed-length rings and tubes to achieve any required back focus distance. Using solid, fixed-length rings like this 10mm version ensures a rigid, tilt-free connection that is often superior to adjustable spacers.

T-2(F)/T-2(F) indicates that the ring has female T-2 threads on both faces. This allows it to function as a coupler, joining two components that both have male T-2 threads.

Yes, the T-2 thread is a widely adopted industry standard in astrophotography, often referred to simply as a "T-thread." This Baader ring will connect to any standard male T-2 thread, regardless of the accessory's manufacturer.

While variable spacers offer convenience, a fixed-length, solid ring like the Baader 10mm provides superior rigidity. This minimizes the risk of tilt or flexure in the optical train, which is critical for maintaining sharp stars across the entire image field, especially when using heavier cameras or filter wheels.