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IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
Shelyak T-mount – 31.75mm nosepiece adapter ring

Shelyak T-mount – 31.75mm nosepiece adapter ring

by Shelyak
SKU SHK-PU0124
$53.00 - $53.00
$53.00
$53.00 - $53.00
$53.00
Price Match Policy!
  • Connects M42x0.75mm T-mount accessories to 1.25" focusers
  • Enables secure threaded attachment for cameras and spectroscopes
  • Standard 31.75mm (1.25") barrel diameter
  • Low-profile design minimizes back focus consumption
  • Black anodized aluminum construction
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • T-mount – 31.75mm nosepiece adapter ring

    This adapter bridges the critical gap between accessories using standard M42x0.75mm T-threads and any telescope equipped with a 1.25" (31.75mm) focuser or eyepiece holder. It provides a secure, threaded connection essential for astrophotography and spectroscopy, replacing the simple slip-fit of a standard 1.25" barrel.

    Connect M42 T-Threads to Any 1.25" Focuser

    The M42x0.75mm thread, commonly known as the T-mount or T-thread, is a universal standard for cameras, filter wheels, and scientific instruments. This adapter allows you to attach any such device to the most common telescope format—the 1.25" barrel—ensuring a rigid, non-flexing connection that is critical for sharp imaging.

    Essential for Lightweight Spectroscopes and DSLR Imaging

    This adapter is the key component for mounting lightweight instruments that require a T-thread interface. It is used to attach a DSLR camera body (via its own T-ring) to a 1.25" focuser for prime-focus imaging or to mount a spectroscope like the Shelyak Alpy 600 or Star'Ex for scientific analysis. It's also the required piece for using a Star Analyser 100 grating with a digital camera body. Please note: this adapter is intended for lighter accessories; heavier imaging trains should use a larger 2" connection to prevent focuser strain. This component is included as a standard part with the Alpy 600 spectroscope.

  • What is the T-mount – 31.75mm nosepiece adapter for?

    This adapter allows you to connect any accessory that has a female M42x0.75mm T-thread to a standard 1.25" (31.75mm) telescope focuser. It converts the threaded T-mount into a simple barrel that can be inserted and secured just like an eyepiece.

    Can I use this T-mount adapter to attach my DSLR to my telescope?

    Yes. You will need two components: a T-ring specific to your camera brand (e.g., Canon, Nikon, Sony) and this T-mount to 1.25" adapter. The T-ring attaches to your camera body, and this adapter threads into the T-ring, allowing the entire assembly to slide into your telescope's 1.25" focuser.

    Is this T-mount adapter compatible with the Shelyak Alpy 600 spectroscope?

    Yes, it is fully compatible. In fact, this exact adapter is included with the Shelyak Alpy 600 spectroscope as the standard method for attaching the instrument to a telescope's 1.25" focuser.

    How do I attach a Star Analyser 100 to my DSLR using this adapter?

    To use a Star Analyser 100 grating with a DSLR for stellar spectroscopy, you first attach a T-ring to your camera. Then, you thread this T-mount to 1.25" adapter into the T-ring. Finally, you thread the Star Analyser 100 into the filter threads on the base of this adapter's 1.25" barrel before inserting the whole assembly into the telescope.

    Will this adapter cause vignetting with my APS-C camera on an f/10 SCT?

    Generally, no. The 1.25" barrel format can cause some corner illumination drop-off (vignetting) on larger APS-C sensors, especially in faster optical systems. However, in a slow f/10 system like a Schmidt-Cassegrain Telescope (SCT), the light cone is narrow enough that vignetting is typically minimal and can be easily corrected with flat frames.

    Are the threads on this T-mount adapter M42x0.75mm or M42x1mm?

    The threads are M42x0.75mm. This is the standard "T-thread" or "T-mount" used in astronomy and photography. It is not compatible with M42x1mm threads (often called Pentax screw mount) found on some older camera lenses.

  • Adapter Type T-Mount to 1.25" Nosepiece
    Telescope Side 1.25" (31.75mm) Barrel
    Accessory Side Male M42x0.75mm T-Threads

    • T-mount – 31.75mm nosepiece adapter ring

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  • Shelyak 1-Year Warranty