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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.
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 40mm Extension Tube for ESATTO 3"

PrimaLuceLab 40mm Extension Tube for ESATTO 3"

by PrimaLuceLab
SKU PLL-PL3600317
$125.00 - $125.00
$125.00
$125.00 - $125.00
$125.00
Price Match Policy!
  • Adds 40mm of back focus for ESATTO 3" focusers
  • Enables focus with long-travel telescopes like refractors
  • Precise dovetail coupling system for rigidity
  • Allows manual focuser rotation for camera framing
  • Features 3 locking screws set at 120° for a secure, no-tilt connection
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • PrimaLuceLab 40mm Extension Tube for ESATTO 3"

    The PrimaLuceLab 40mm Extension Tube solves critical back focus issues when installing the ESATTO 3" on telescopes with long-travel stock focusers. Its integrated dovetail system, secured by 3 screws set at 120° intervals, also provides manual rotation for precise camera framing.

    Bridge the 40mm Back Focus Gap for ESATTO 3"

    The ESATTO 3" is a micrometric focuser, engineered for high-precision adjustments rather than extensive draw tube travel. When retrofitting it onto telescopes like refractors that often feature long-travel stock focusers, this 40mm extension tube provides the necessary spacing to bring your camera and accessories to the focal plane.

    Frame Your Target with the 3-Screw, 120° Lock System

    This is more than a simple spacer. The extension incorporates a precise dovetail coupling system that allows you to manually rotate the entire ESATTO 3" focuser. By loosening the three locking screws, you can orient your imaging train for optimal composition of celestial objects, then tighten them down for a rigid, flex-free connection. The 120° spacing of the screws ensures the load is distributed evenly, preventing any tilt in the optical path.

    Choosing Your Extension: 40mm vs. 65mm for ESATTO 3"

    PrimaLuceLab also offers a 65mm extension for the ESATTO 3". The correct choice depends entirely on your telescope's specific back focus requirements. The 40mm extension is ideal for setups that need a moderate amount of additional spacing to reach focus. For systems with even longer focal paths, the 65mm version may be required. Always measure your required back focus before selecting an extension.

  • Why do I need this 40mm extension for my ESATTO 3"?

    Many stock focusers, especially on refractor telescopes, have a long range of travel. The ESATTO 3" is a high-precision robotic focuser with a shorter, more exact travel range. The 40mm extension tube compensates for this difference, adding the fixed spacing needed to ensure your camera can reach focus with the ESATTO 3".

    How does the rotational adjustment on the 40mm ESATTO 3" extension work?

    The extension features a dovetail mechanism with three locking screws set at 120-degree intervals around its body. To rotate your focuser:

    • Slightly loosen the three screws.
    • Manually rotate the connected ESATTO 3" focuser to your desired orientation.
    • Re-tighten the three screws to lock it securely in place.

    This allows you to perfectly frame objects like the Andromeda Galaxy (M31) or manage cable routing without disassembling your imaging train.

    When should I choose the 40mm ESATTO 3" extension over the 65mm version?

    The choice depends on your specific telescope and imaging train. The 40mm extension is suitable when you need a moderate amount of extra back focus. If you find your ESATTO 3" runs out of inward travel and is still far from focus, you likely need a longer extension like the 65mm version. It's best to measure the focus position with your original focuser to determine the required extension length.

    Will adding the 40mm extension tube introduce flexure to my imaging setup?

    No. The PrimaLuceLab 40mm extension is designed for rigidity. The precise dovetail coupling and the three-screw locking system create a solid, stable connection between the telescope and the ESATTO 3" focuser, preventing tilt and flexure even with heavy imaging loads.

    Can I use the 40mm extension tube with a Ritchey-Chrétien telescope?

    While this extension is primarily designed to solve the travel-length issue common with refractors, it can be used on any telescope where the ESATTO 3" requires exactly 40mm of additional spacing to reach focus. For specific telescopes like large GSO/Orion/TPO Ritchey-Chrétiens, PrimaLuceLab makes dedicated adapters (like PL3600236) which may be more suitable as they adapt the thread type as well as providing spacing.

    Can I stack multiple 40mm ESATTO 3" extension tubes?

    Stacking extensions is generally not recommended as each connection point is a potential source of tilt or flexure. If you require more than 40mm of spacing, it is mechanically superior to use a single, longer extension, such as the 65mm version for the ESATTO 3", to ensure maximum rigidity for your imaging train.

  • PrimaLuceLab 1-Year Warranty