-
Achieve Perfect Back Focus with the ZWO T2 Extension
The ZWO T2 Female to Female Adapter is a fundamental component for any astrophotographer building a precise imaging train. This 11mm T2 extension ring provides a rigid, measured space, allowing you to connect two male T2-threaded accessories and achieve the critical 55mm back focus distance required by most cameras and corrector systems. It is the simple, reliable solution to a problem every imager faces: connecting components while maintaining perfect sensor distance.
Dual T2 Female Threads for Universal Connection
This adapter is built around the universal T2 thread standard (M42x0.75), ensuring broad compatibility across the ZWO ecosystem and with equipment from other manufacturers. By featuring female threads on both sides, it acts as a coupler, securely joining male-threaded components like off-axis guiders, filter wheels, or other T2 extension tubes. This design allows you to bridge gaps in your imaging train without introducing flexure or alignment errors.
The 11mm Optical Length for Precise Spacing
The core function of this adapter is its fixed 11mm optical length. When paired with a 6.5mm back focus ZWO ASI camera, a filter wheel (20mm), and an off-axis guider (16.5mm), the total distance adds up to 54mm. This 11mm spacer is often the final piece needed to reach the standard 55mm back focus, ensuring your field corrector performs as designed for sharp stars across the entire frame.
Using a single, solid extension is always preferable to stacking multiple thin, unthreaded spacers. A solid, threaded component like this 11mm adapter maintains better optical alignment and rigidity, reducing the potential for sensor tilt that can ruin an otherwise perfect exposure. It's an investment in mechanical stability for a better final image.
Lightweight, Non-Reflective Construction
Machined from black anodized aluminum, the ZWO T2 adapter is both lightweight and durable. The anodized finish provides a tough, scratch-resistant surface, while the matte black interior minimizes internal reflections. This attention to stray light control is critical, as it prevents unwanted glare and ghosting from degrading the contrast of your deep-sky images.
One honest limitation of any fixed-length spacer is its lack of adjustability. If your required back focus is not a standard distance, you may need a variable extension or a combination of different fixed spacers. This 11mm adapter is purpose-built for the most common ZWO imaging configurations; measure your required distance carefully before purchasing.
-
Which ZWO spacer do I need for 55mm back focus?
To calculate the right spacer, add up the back focus of your components (camera, filter wheel, OAG) and subtract the total from 55mm. For a common ZWO setup with a camera (17.5mm), filter wheel (20mm), and OAG (16.5mm), the total is 54mm. This 11mm spacer is designed to bridge the gap between the camera and filter wheel in that configuration.
Will this T2 extension work with non-ZWO equipment?
Yes. The T2-thread (M42x0.75) is an industry standard for astronomy accessories. This adapter will connect to any component that uses male T2 threads, regardless of the manufacturer.
Does this adapter cause tilt in the imaging train?
This is a solid, machined ring designed to minimize tilt. Compared to stacking multiple thin, unthreaded shims, a single threaded spacer like this provides a much more rigid and square connection, reducing the risk of sensor tilt.
Can I use this for visual observing?
While primarily designed for imaging, you can use it to add spacing in a visual train if you need to extend an eyepiece or accessory to reach focus. However, its main purpose is for achieving precise back focus in astrophotography.
Why use a female-to-female adapter instead of male-to-female?
A female-to-female adapter acts as a coupler, joining two components that both have male threads. This is common when connecting a filter wheel directly to an off-axis guider or other male-threaded accessory in your imaging train.
-
| Product Code |
T2-T2-11 |
| Optical Length |
11mm |
| Thread Type |
M42x0.75 (T2-Thread) |
| Connection Side 1 |
T2 Female |
| Connection Side 2 |
T2 Female |
| Material |
Black Anodized Aluminum |
| Outer Diameter |
48mm |
-
-
ZWO T2 Female to Female Adapter - 11mm
× 1
-
-
No manual is required for this product.
-
ZWO 2-Year Warranty
