What is the main purpose of this M68 to M63 adapter?
This adapter is designed to connect a field flattener or reducer with a female M63x1.0mm thread (like those from Riccardi or William Optics) to a focuser, rotator, or other accessory that has a female M68x1.0mm thread. It allows you to integrate these specific optical correctors into a larger-format imaging train.
Why is the 1.4 mm thickness of the adapter important?
The 1.4 mm thickness is critical for preserving backfocus. Reducers and flatteners have a very specific required distance to the sensor plane. A thick adapter can consume too much of this distance, leaving no room for other essential accessories like filter wheels or off-axis guiders. This adapter's thin profile minimizes its impact on your optical path.
How do I know if my reducer is compatible with this M68 to M63 adapter?
You need to verify that your reducer has a female M63 thread with a 1.0mm pitch. This is a common standard for many Riccardi and William Optics reducers, but it's essential to check your specific model's documentation to confirm the thread size and pitch before purchasing.
Can I use this adapter to connect my M63 reducer to a Sky-Watcher Esprit 100ED focuser?
Many Sky-Watcher Esprit focusers terminate in a female M68x1.0mm thread, making this adapter a potential solution. However, you must confirm the thread specification of your specific focuser model and ensure that the total backfocus of your imaging train, including the 1.4 mm from this adapter, matches the requirement of your reducer.
Will this M68 to M63 adapter cause any vignetting with a full-frame sensor?
The M63 clear aperture is generally sufficient for full-frame sensors when used with a compatible reducer designed for that format. The adapter itself has a clear internal diameter defined by the M63 thread and should not introduce additional vignetting beyond what the reducer itself produces.
Is the thread pitch of 1.0mm standard for both the M68 and M63 sides?
Yes. This adapter uses a 1.0mm pitch for both the M68 and M63 male threads. This is a common standard in astronomy, but other pitches (like 0.75mm) exist for different threads, so always verify that both your focuser and reducer use the 1.0mm pitch standard.