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SBIG T-Thread Visual Back
The SBIG T-Thread Visual Back provides a direct mechanical interface, converting the common SCT 2in-24tpi rear cell thread to the universal M42x0.75 T2 standard. This adapter gives a rigid, threaded imaging train and is supported by a 1-year manufacturer warranty.
SCT 2in-24tpi to M42x0.75 T-Thread Adaptation
This adapter creates a direct, threaded connection between the rear cell of a Schmidt-Cassegrain telescope and any T-threaded accessory. By replacing a standard slip-fit visual back that relies on thumbscrews, the SBIG T-Thread Visual Back eliminates a potential source of flexure, tilt, and rotation in your optical train. This rigid connection is critical for astrophotography, ensuring your camera remains perfectly aligned with the telescope's optical axis throughout an imaging session.
The telescope side features a female SCT 2in-24tpi thread for small SCTs, while the accessory side provides a male M42x0.75 T-thread. This makes it compatible with T-thread camera fronts such as the SBIG STC-7 front T-Thread mount.
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What is the primary purpose of the SBIG T-Thread Visual Back?
The primary purpose of the SBIG T-Thread Visual Back is to adapt the SCT 2in-24tpi thread on the rear of a Schmidt-Cassegrain telescope to the widely used M42x0.75 (T2) thread. This allows you to securely attach T-threaded cameras and other imaging accessories directly to your telescope.
Which telescopes is the SBIG T-Thread Visual Back compatible with?
This adapter is designed for small Schmidt-Cassegrain Telescopes (SCTs) that feature the standard 2-inch, 24-threads-per-inch (2in-24tpi) male thread on their rear cell.
What is the advantage of using this SBIG adapter over a standard visual back with thumbscrews?
A threaded connection is significantly more rigid and secure than a slip-fit connection held by thumbscrews. The main advantages are:
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No Tilt: It ensures the camera sensor is perfectly perpendicular to the light path.
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No Flexure: It prevents heavy cameras or accessories from sagging.
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No Rotation: Your camera and framing will not accidentally rotate during an exposure.
Will the SBIG T-Thread Visual Back work with my small SCT and an SBIG STC-7 camera?
Yes. A small SCT with a 2in-24tpi rear thread fits the telescope side of this adapter. The SBIG STC-7 front T-Thread mount (M42x0.75) threads onto the accessory side of the visual back, creating a secure connection.
What are the thread specifications for the SBIG T-Thread Visual Back?
The adapter has two threads:
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Telescope Side: Female SCT thread (2in-24tpi)
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Camera/Accessory Side: Male T-thread (M42x0.75), also known as T2.
How do I install the SBIG T-Thread Visual Back?
Installation is straightforward. First, unthread the existing visual back or any other accessory from the rear cell of your SCT. Then, carefully thread the SBIG T-Thread Visual Back onto the exposed male 2in-24tpi threads until it is snug. Do not overtighten. Your T-threaded accessories can then be attached to the male M42x0.75 threads on the adapter.
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| Telescope-side connection |
SCT 2in-24tpi |
| Camera-side connection |
M42x0.75 (T2) |
| Warranty |
1 year |
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SBIG T-Thread Visual Back
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- Diffraction Limited 1-Year Warranty
