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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.
PrimaLuceLab Adapter from M81 to M57 with Stop Ring for ESATTO 3"

PrimaLuceLab Adapter from M81 to M57 with Stop Ring for ESATTO 3"

by PrimaLuceLab
SKU PLL-PL3600279
$95.00 - $95.00
$95.00
$95.00 - $95.00
$95.00
Price Match Policy!
  • Connects M57 accessories to M81 threads
  • Compatible with ESATTO 3" and ARCO 3"
  • Adds only 4mm of optical length
  • Includes a stop ring for precise 360° camera rotation
  • Threads directly to the focuser or rotator draw tube
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • PrimaLuceLab Adapter from M81 to M57 with Stop Ring for ESATTO 3"

    The PrimaLuceLab Adapter from M81 to M57 with Stop Ring for ESATTO 3" provides a secure, low-profile connection for your imaging train, converting the M81 thread of the focuser drawtube to a standard M57 female thread. This adapter adds only 4mm of total optical length, preserving precious back focus for connecting cameras and accessories like filter wheels or off-axis guiders.

    Secure M57 Connection with a 4mm Optical Path

    This adapter threads directly onto the M81 draw tube of your ESATTO 3" focuser or ARCO 3" rotator, providing a robust M57 female thread for your equipment. The assembly consists of the 1.5mm adapter and a 2.5mm stop ring, consuming a minimal 4mm of back focus to maintain compatibility with complex imaging trains.

    The included stop ring is the critical component for precise framing. It allows you to rotate your attached camera to any angle and then lock it securely in place, ensuring your imaging sensor is perfectly aligned with your target without having to unthread your entire camera setup.

  • What is the primary function of the PrimaLuceLab M81 to M57 adapter?

    This adapter allows you to connect any camera or accessory that has a female M57 thread to the male M81 thread found on the draw tube of the PrimaLuceLab ESATTO 3" robotic focuser and ARCO 3" rotator.

    How does the stop ring on the PrimaLuceLab M81 to M57 adapter work?

    The stop ring threads onto the M57 male thread of the adapter before you attach your camera. It acts as a counter-locking mechanism, allowing you to thread your camera on, rotate it to the desired angle for perfect framing, and then tighten the stop ring against the camera body to lock it in that position.

    What is the total optical length of the PrimaLuceLab M81 to M57 adapter?

    The total optical length is 4mm. This is composed of the main adapter body (1.5mm) and the stop ring (2.5mm).

    Can I use this PrimaLuceLab M81 to M57 adapter with the ARCO 3" rotator?

    Yes, this adapter is fully compatible with both the ESATTO 3" focuser and the ARCO 3" rotator, as both units use the same M81 female thread on their draw tubes for attaching accessories.

    I need to connect my camera with an M57 thread to my ESATTO 3" focuser. Is the PrimaLuceLab M81 to M57 adapter the correct part?

    Yes, this is the exact part designed for that purpose. It converts the large M81 thread of the ESATTO 3" to the widely used M57 thread, allowing you to securely attach your camera.

    How do I use the PrimaLuceLab M81 to M57 adapter to frame the Andromeda Galaxy (M31) with my rectangular camera sensor?

    The stop ring is essential for this. After attaching the adapter and your camera to your ESATTO 3", you can loosen the stop ring slightly, rotate the camera body until the long axis of your sensor aligns with the longest dimension of the Andromeda Galaxy (M31), and then tighten the stop ring to fix the camera in that orientation for your exposure sequence.

  • Focuser Side Connection M81 Male Thread
    Accessory Side Connection M57 Female Thread (via M57 Male thread on adapter)
    Total Optical Length 4mm
    Adapter Body Length 1.5mm
    Stop Ring Length 2.5mm
    Compatibility PrimaLuceLab ESATTO 3", PrimaLuceLab ARCO 3"
    Primary Function Thread reduction and camera rotation

    • Adapter from M81 to M57

      × 1

    • M57 Stop Ring

      × 1

  • PrimaLuceLab 1-Year Warranty