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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.
Baader M68 Extension Tube - 20mm

Baader M68 Extension Tube - 20mm

by Baader Planetarium
SKU BAA-2458202
$81.00 - $81.00
$81.00
$81.00 - $81.00
$81.00
Price Match Policy!
  • Adds a fixed 20mm of back focus
  • Features large M68 x 1 threads for rigid, no-flex connections
  • Integral part of the Baader M68 Tele-Compendium system
  • Prevents tilt common in heavy, slip-fit imaging trains
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Baader M68 Extension Tube - 20mm

    The Baader M68 Extension Tube adds exactly 20mm of spacing to your imaging train, using the large-format M68 x 1 thread to create a rigid connection that eliminates the tilt and flexure common with slip-fit adapters. For professional-level astrophotography and spectroscopy, where any amount of mechanical shift can render data unusable, this threaded extension is a fundamental component for building a solid optical system.

    The M68 Standard: A 20mm Rigid Extension

    Unlike standard 2-inch nosepieces that can sag or tilt under the weight of a heavy camera, the M68 system provides a secure, screwed-in connection. This 20mm extension tube maintains that rigidity while allowing you to achieve precise back focus spacing for flatteners, reducers, or other corrective optics. The large diameter of the M68 thread ensures a stable, robust link between components, preserving the mechanical alignment of your entire imaging train.

    Building a Flex-Free M68 Imaging Train: The 20mm Component

    This extension tube is a modular building block within the Baader M68 Tele-Compendium system. This system is designed to solve the critical problem of flexure in long optical setups, such as those using telecentric systems for H-alpha solar work or Fluorite Flatfield Converters (FFC) for high-resolution planetary imaging. By combining this 20mm tube with other M68 components, you can construct a variable-length adapter that is both a precise spacer and an effective stray light shield, ensuring maximum contrast and mechanical stability.

  • What is the primary purpose of the Baader M68 20mm Extension Tube?

    Its main purpose is to add a fixed 20mm of length to an optical train while maintaining a rigid, flex-free connection using the M68 thread standard. This is critical for astrophotography setups where mechanical stability is paramount.

    How does this M68 extension tube help when imaging with a heavy camera and telecentric system?

    Heavy accessories connected via simple slip-fit adapters (like a 2" nosepiece) are prone to tilting under their own weight, which ruins optical alignment. The Baader M68 extension tube replaces that weak link with a solid, threaded connection that physically cannot tilt, ensuring your camera and any other accessories remain perfectly square to the optical axis.

    Why is the M68 thread used for this Baader extension tube?

    The M68 thread is a large-diameter connection standard, famously used on professional Zeiss telescopes. Its size and robust threading are ideal for supporting heavy imaging trains without any flexure, making it the superior choice for securely connecting modern cameras, filter wheels, and corrective optics.

    Is the Baader 20mm M68 Extension Tube part of a larger system?

    Yes, it is a modular component of the Baader M68 Tele-Compendium system. This system allows an imager to build a variable-length, rigid adapter and light shield assembly from various M68-threaded tubes and adapters to suit the specific needs of their setup.

    If my focuser uses a 2" clamp, can I use this M68 extension tube?

    Not directly. This tube is designed to be part of a fully M68-threaded optical train. To use it with a standard 2" focuser, you would first need an adapter that converts your focuser's 2" clamp output to a male M68 thread, creating a secure base for the rest of the M68 system.

    Besides adding 20mm of length, what other benefit does this Baader M68 tube provide?

    When used as part of the Tele-Compendium system, the tube's carefully blackened interior walls also function as an effective stray light shield. This helps to block off-axis light from entering the optical path, which significantly improves image contrast, especially when imaging faint objects.

  • Net weight (kg) 0.05
    Compatible Brands Baader Planetarium, Zeiss
    Inner Diameter / Clear Aperture (mm) 62
    Outer Diameter 76
    Type of Adapter Extension
    Optical length (mm) 20
    Usage serves as additional focus distance for eyepiece projection or FFC
    Inner Connection (eyepiece/-camera-sided) M68 x 1
    Outer Connection (lens sided) M68 x 1
    Adapters Family M68 System
  • Baader Planetarium Warranty