How do I know if I need the ZWO M42 Sensor Tilt Plate?
If you notice that stars are sharp in the center of your images but appear stretched or out of focus in one or more corners, you likely have sensor tilt. This is most apparent in telescopes with fast focal ratios (f/5 or lower) and with larger sensors like the APS-C format found in the ZWO ASI2600. The M42 tilt plate provides the necessary adjustments to correct this and achieve a perfectly flat field.
Can I use the ZWO M42 plate to connect my M68 OAG to a refractor with an M42 focuser?
Yes, this is one of its primary functions. The ZWO M42 Sensor Tilt Plate is specifically designed to bridge the connection between ZWO's M68 OAG and a telescope that has a male M42x0.75 thread on the focuser drawtube. It allows you to build a fully threaded imaging train for guiding and filtering.
How much back focus does the ZWO M42 Sensor Tilt Plate consume?
The plate itself has a thickness of 5mm. You must account for this 5mm in your total back focus calculation. For ZWO cameras that typically have a 55mm back focus requirement, this plate will be one component of that total distance.
Is this plate compatible with cameras other than the ZWO ASI2600?
Yes. While it is designed with the ASI2600 in mind, it is compatible with any camera that has female M42x0.75 (T2) threads and would benefit from tilt adjustment. It is particularly useful for any camera with an APS-C or smaller sensor.
How do you adjust the tilt on the ZWO M42 plate?
The plate uses a push-pull screw system. You will typically see sets of small screws around the perimeter of the plate. To make an adjustment, you slightly loosen one screw (the "pull" screw) and then gently tighten the opposing screw (the "push" screw) to tilt the plate in that direction. The process involves taking test exposures and making small, iterative adjustments until the corner stars are sharp across the entire field.
Will the ZWO M42 Sensor Tilt Plate cause vignetting with a full-frame sensor?
Yes, it is likely to cause vignetting with full-frame (36mm x 24mm) sensors. The M42 (42mm) clear aperture is optimized for APS-C sensors (around 28mm diagonal) and smaller. For full-frame cameras, you should use a tilt plate with a larger M48 or M54 aperture to avoid darkening the corners of your images.
