What is the primary purpose of the Baader 3"i to M68a Adapter?
Its sole purpose is to connect specific imaging accessories—namely FLI filter wheels and SBIG STX series cameras—that use a 3" internal thread to an optical train that uses the Baader M68 external thread system. It acts as a reducer and thread converter.
What do the "3"i" and "M68a" designations mean on this adapter?
"3"i" refers to the female (internal) 3-inch thread on one side of the adapter, which matches the male thread on the FLI and SBIG devices. "M68a" refers to the male (external) M68 x 1mm thread on the other side, which connects to the rest of the Baader M68 system.
Why would I use the Baader M68 system with my SBIG STX camera?
The Baader M68 system provides a large, rigid, and fully-threaded connection path that is superior to standard 2" or T-2 systems. For large-format sensors like those in SBIG STX cameras, the M68 standard helps prevent vignetting (darkening of the corners of the image) and flexure, ensuring a solid and stable imaging train.
Is this Baader adapter compatible with all SBIG or FLI cameras?
No, it is not. This adapter is specifically designed for the 3" internal thread found on certain FLI Color Filter Wheels (CFW) and SBIG STX series cameras. You must verify that your specific piece of equipment has this exact thread before purchasing.
Can I use this adapter to connect my FLI filter wheel directly to a telescope's 2" focuser?
No. This adapter terminates in a male M68 thread, not a 2" nosepiece. To connect to a 2" focuser, you would need an additional adapter that steps down from the M68 thread to a standard 2" barrel, such as the Baader M68 to 2" adapter.
Do I need this adapter if my system is already based on 3" threads?
If your entire optical train, from the focuser to the camera, uses a consistent 3" threaded connection, you likely do not need this adapter. This part is specifically for converting the 3" thread on the camera or filter wheel to the M68 standard for integration with other M68 components.
