A part of their modular Astro T-2 system, the Alpine Astronomical Baader Wide T-Ring Set is made up of two parts: The camera-specific bayonet mount ring and an inner adapter ring with standard T-2 female threads. The bayonet ring is designed specifically to fit Canon EOS DSLR cameras and provides a safe and secure connection.
Out of the box, it will work like a conventional T-ring: It is compatible with all T-2 accessories on the market—including Baader's entire T-2 Astro modular line. But unlike conventional rings, the inner threaded ring can be unmounted from the bayonet ring, allowing the bayonet ring to be used with Baader's S52 rings and accessories. Removing the inner T-2 adapter presents a larger clear aperture than a normal T-ring, which is good for full-frame cameras.
The bayonet ring can also be directly mounted to Baader's Universal Filter Changer (UFC) System without the need for additional adapters. This direct-connection capability provides a solid connection without adding any optical distance. Additionally, a more conventional 2" nosepiece can be installed on the bayonet ring in place of the T-2 ring for mounting your camera body directly into 2" eyepiece holders or accessories.