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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 M48 Extension Tube 40mm / 2" Nosepiece with Safety Kerfs

Baader M48 Extension Tube 40mm / 2" Nosepiece with Safety Kerfs

by Baader Planetarium
SKU BAA-2958640
$49.00 - $49.00
$49.00
$49.00 - $49.00
$49.00
Price Match Policy!
  • Adds a fixed 40mm of optical path length
  • Functions as both an M48 extension tube and a 2" nosepiece
  • Features M48 x 0.75 female and male threads for secure connection
  • Machined with Baader Safety Kerfs to prevent slippage from the focuser
  • Internal surfaces are blackened to minimize stray light reflections
1 in stock
Qualifies for FREE Shipping in CONUS on orders over $350.
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • Baader M48 Extension Tube 40mm / 2" Nosepiece with Safety Kerfs

    The Baader M48 Extension Tube provides exactly 40mm of rigid extension for M48-threaded imaging trains and doubles as a standard 2" nosepiece. This dual-function component is essential for achieving the precise back focus required by field flatteners and focal reducers, especially with modern cameras that have minimal optical height.

    Achieving Critical 40mm Spacing with M48 Threads

    Correct spacing is non-negotiable for achieving a flat, well-corrected field. This tube delivers a fixed 40mm extension, eliminating the potential for tilt that can occur when stacking multiple shorter extenders. The M48 (48mm x 0.75) threads provide a wide, secure, and non-vignetting connection for full-frame sensors and other large-format cameras, ensuring your entire optical train is rigidly coupled.

    A Secure 2" Nosepiece with Baader Safety Kerfs

    Beyond its function as an extender, this component serves as a robust 2" nosepiece. It inserts directly into any 2" focuser, visual back, or diagonal. Baader's signature Safety Kerfs—two distinct grooves machined into the barrel—provide an essential safety measure. These kerfs give your focuser's compression ring or thumbscrew a secure purchase, preventing the nosepiece and your expensive camera from accidentally slipping out.

    Built for Modern Cameras with a 3mm Thread Depth

    As modern astronomy cameras are designed with increasingly short optical heights, older accessories can cause problems with threads bottoming out. Baader engineers their new M48 components with a 3mm thread depth standard. This thoughtful design ensures full, secure engagement with contemporary cameras and accessories without interference, maintaining perfect alignment in your imaging setup.

  • What is the primary function of the Baader M48 40mm Extension Tube?

    Its primary function is to add a precise 40mm of distance to an M48-threaded optical train. This is crucial for achieving the correct back focus distance for accessories like field flatteners, reducers, or off-axis guiders to ensure sharp stars across the entire image field.

    What are the "Safety Kerfs" on this Baader 2" nosepiece?

    The Safety Kerfs are two recessed grooves machined into the 2" barrel. They act as a safety catch for your focuser's thumbscrew or compression ring. If the screw loosens slightly, its tip will catch in the groove, preventing your camera and the nosepiece from falling to the ground.

    Can I thread a 2" filter into the Baader M48 Extension Tube?

    Yes. The female M48 thread on this extension tube is the standard thread for 2" astronomy filters. You can thread a 2" filter directly into the front of the extension tube before inserting it into your focuser or attaching it to your optical train.

    I need exactly 40mm of spacing for my flattener with my full-frame camera. Is this Baader extension the right part?

    Yes, this is an ideal solution. Using a single, solid 40mm extension like this one is mechanically superior to stacking multiple shorter extensions, as it minimizes the risk of tilt and flexure. The M48 threads also prevent vignetting on large, full-frame sensors.

    Will this Baader nosepiece fit my Schmidt-Cassegrain's 2" visual back?

    Absolutely. The 2" barrel is designed to fit any standard 2" focuser, visual back, or diagonal, including those found on Schmidt-Cassegrain telescopes. The Safety Kerfs provide extra security, which is especially valuable when mounting heavier cameras on an SCT.

    Why does Baader use a different thread depth on their newer M48 parts like this 40mm tube?

    Baader adapted their M48 and T-2 parts to a modern 3mm thread depth standard to accommodate the trend of modern cameras having very short body depths. This prevents the threads of the extension tube from bottoming out inside the camera or accessory, ensuring a flush, secure fit without damaging any internal components.

  • Extension Provided 40mm
    Barrel Diameter 2"
    Threads M48 x 0.75 (Female and Male)
    Safety Feature Baader Safety Kerfs
    Net weight (kg) 0.05
    Compatible Brands Baader Planetarium
    Clamping System no clamp
    Inner Diameter / Clear Aperture (mm) 45 mm
    Outer Diameter 53 mm
    Type of Adapter Nosepiece, Extension
    Optical length (mm) 40 (or 4)
    Usage Adjusting the distances of accessories with M48 thread, M48 / 2" Nosepiece
    Outer Connection (eyepiece/-camera-sided) M48
    Inner Connection (lens sided) ø 2" (50.8mm), M48
    Adapters Family M48 System

    • Baader M48 Extension Tube 40mm / 2" Nosepiece

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  • Baader Planetarium Warranty