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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.
Askar M54/M48 T-Ring for Canon EOS-R

Askar M54/M48 T-Ring for Canon EOS-R

by Askar
SKU ASK-ASKADA54CA
$43.00 - $43.00
$43.00
$43.00 - $43.00
$43.00
Price Match Policy!
  • Securely adapts Canon EOS-R mirrorless camera bodies
  • Connects to M54x0.75 and M48x0.75 threaded correctors
  • Integrated rotational adjuster for fine backfocus control
  • Precision CNC-machined for rigidity and perfect alignment
  • Laser-engraved scale for repeatable spacing adjustments
1 in stock
Qualifies for FREE Shipping in CONUS on orders over $350.
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Askar M54/M48 T-Ring for Canon EOS-R

    The Askar M54/M48 T-Ring for Canon EOS-R provides a solid, direct-thread connection between your camera and your telescope's M54 or M48 corrector, incorporating a fine adjustment mechanism to precisely set the critical backfocus distance required for sharp stars across a full-frame sensor.

    Secure Canon EOS-R to M54/M48 Connection

    This adapter provides a rigid, flex-free link between your Canon EOS-R camera and the large-format correctors found on modern astrographs. By threading directly to the M54 or M48 threads on your flattener or reducer, it eliminates the potential for tilt that can occur with multi-part adapter chains, ensuring your camera sensor remains perfectly orthogonal to the optical axis.

    Integrated Backfocus Adjustment for Perfect Stars

    Achieving the precise backfocus distance specified by your field flattener or reducer is critical for sharp stars at the edge of the frame. This Askar T-Ring features an integrated rotational adjuster that allows you to make minute changes to your sensor spacing without guesswork or stacks of shims. A laser-engraved scale provides a clear reference for repeatable results, and two locking screws secure your setting once it's dialed in perfectly.

  • What is the Askar M54/M48 T-Ring for Canon EOS-R used for?

    This adapter connects a Canon EOS-R mount mirrorless camera to a telescope's field flattener or reducer that has either M54x0.75 or M48x0.75 male threads. It also includes a built-in mechanism to make fine adjustments to the backfocus, which is the critical distance between the corrector lens and the camera sensor.

    Which Askar telescopes is this Canon EOS-R adapter designed for?

    This adapter is ideal for any Askar astrograph or other telescope that uses a field flattener or reducer with an M54 or M48 threaded output. It is particularly useful for full-frame imaging with refractors like the Askar FRA series or PHQ apos, ensuring a wide, unvignetted illumination of the Canon R sensor.

    Why is backfocus adjustment so critical when imaging with a Canon EOS-R on a refractor?

    Field flatteners and focal reducers are designed to work at a very specific distance from the camera sensor, often with a tolerance of less than a millimeter. If this distance is off, stars in the corners of your images of targets like the Pleiades (M45) will appear elongated or out of focus. This adapter's built-in adjustment allows you to precisely dial in that spacing for perfectly sharp stars across the entire full-frame sensor of your Canon EOS-R.

    How do I use the adjustment feature on this Askar T-ring?

    To adjust the backfocus, you first loosen the two small locking screws on the side of the adapter. You can then rotate the main body of the adapter to increase or decrease the spacing. The laser-engraved scale provides a reference for how much you have adjusted. Once you achieve perfect focus in the corners of your test images, you tighten the locking screws to fix the position.

    Will this adapter work with my Canon EF-mount DSLR camera?

    No. This adapter is specifically designed for the Canon RF mount used on EOS-R series mirrorless cameras. It will not fit Canon DSLRs that use the older EF or EF-S mount.

    What's the benefit of connecting to M54 threads instead of a standard M42 T-ring?

    A standard M42 T-ring has a smaller inner diameter, which can cause vignetting (darkening of the corners) on full-frame sensors like the one in a Canon EOS-R. The larger M54 thread provides a wider light path, ensuring the entire sensor is fully illuminated by the corrector, which is essential for capturing clean, evenly lit wide-field images.

  • Askar 1-Year Warranty