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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 5mm M48 Extension

PrimaLuceLab 5mm M48 Extension

by PrimaLuceLab
SKU PLL-PL3304805
$29.00 - $29.00
$29.00
$29.00 - $29.00
$29.00
Price Match Policy!
  • Adds a precise 5mm of optical length
  • Standard M48x0.75 male and female threads
  • Knurled exterior for a secure grip
  • Black-anodized aluminum construction minimizes reflections
  • Part of a modular system for custom spacing
1 in stock
Qualifies for FREE Shipping in CONUS on orders over $350.
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • PrimaLuceLab 5mm M48 Extension

    The PrimaLuceLab 5mm M48 Extension is a fundamental component for any M48x0.75 imaging train, providing a rigid, repeatable 5mm of spacing to achieve critical back focus for flatteners, reducers, and off-axis guiders.

    Achieve Critical 5mm Spacing for M48 Imaging Trains

    This extension solves a common problem in astrophotography: hitting the exact back focus distance specified by your optical corrector. Machined from metal with a black anodized finish, it adds exactly 5mm of length between any two components with M48 threads, such as a camera and a filter wheel.

    The interior is also anodized black to prevent stray light from reflecting and reducing contrast in your images. For easy handling in the dark, the exterior features a knurled grip, which is especially useful when tightening or loosening the extension with gloves on.

    A Modular System for Precise Back Focus Accuracy

    While this component provides a fixed 5mm length, it is designed as part of PrimaLuceLab's comprehensive M48 spacing system. You can screw multiple extensions together to create longer, rigid spacers as needed for your specific setup.

    For ultimate precision, this 5mm extension can be combined with PrimaLuceLab's fine-tuning spacers (sold separately). This modular approach allows you to build a custom spacer to the exact length required by your optics, eliminating guesswork and ensuring your stars are sharp from edge to edge.

  • My corrector requires 55mm of back focus, but my setup is at 49mm. How does the PrimaLuceLab 5mm M48 Extension help?

    This is the perfect scenario for the PrimaLuceLab 5mm M48 Extension. By adding this extension into your M48 imaging train, you increase the total distance by exactly 5mm, bringing your 49mm spacing up to the required 55mm. This single component corrects the spacing error precisely.

    How can I use the PrimaLuceLab 5mm M48 Extension to correct the spacing for my ZWO ASI camera and a reducer?

    Most popular reducers require 55mm of back focus. A typical ZWO cooled camera has a native back focus of 17.5mm (or 6.5mm). If the adapters included with your camera don't add up to exactly 55mm, you will need spacers. The PrimaLuceLab 5mm M48 Extension is a common component used to close the remaining gap in the optical train.

    What makes the PrimaLuceLab 5mm M48 Extension different from a generic spacer?

    The key differences are the build quality and system integration. The PrimaLuceLab extension features:

    • A knurled grip: This makes it much easier to tighten and loosen, especially in cold weather.
    • Internal and external anodizing: Reduces the risk of internal reflections that can degrade image contrast.
    • Modular design: It's designed to work seamlessly with other PrimaLuceLab extensions and fine-tuning spacers.

    Can I stack multiple PrimaLuceLab 5mm M48 Extensions together?

    Yes. The extensions feature male threads on one side and female threads on the other, allowing you to screw them together. For example, stacking two 5mm extensions will give you a rigid 10mm spacer.

    Is the inside of the PrimaLuceLab 5mm M48 Extension black anodized?

    Yes. Both the internal and external surfaces are black anodized. The internal treatment is crucial for preventing stray light from reflecting off the spacer walls and onto your camera sensor, which helps maintain high-contrast images.

    What is the knurled grip on the PrimaLuceLab 5mm M48 Extension for?

    The knurled grip provides a textured surface that makes the extension easier to handle and turn by hand. This is a significant ergonomic improvement over smooth-sided spacers, which can be difficult to unscrew if they become too tight, especially when you are wearing gloves.

  • Optical Length 5mm
    Thread Type M48x0.75 (Male on one side, Female on the other)
    Material Metal, Black Anodized
    Exterior Knurled Grip

    • 5mm M48 Extension

      × 1

  • PrimaLuceLab 1-Year Warranty