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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 - 15mm

Baader M48 Extension Tube - 15mm

by Baader Planetarium
SKU BAA-2958615
$40.00 - $40.00
$40.00
$40.00 - $40.00
$40.00
Price Match Policy!
  • Adds exactly 15mm of optical path length
  • M48 x 0.75 female and male threads
  • Compatible with 2-inch filter systems
  • Machined for modern, short back-focus cameras
  • Part of the Baader Astro T-2 and M48 system
1 in stock
Qualifies for FREE Shipping in CONUS on orders over $350.
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Baader M48 Extension Tube - 15mm

    The Baader M48 Extension Tube adds precisely 15mm of spacing to any standard M48 x 0.75 threaded imaging train. It is manufactured to Baader's modern 3mm thread depth standard, ensuring a rigid, light-tight connection for modern astronomy cameras that have minimal back focus distance.

    Achieving Precise 15mm Spacing in M48 Imaging Trains

    Hitting the exact back focus distance specified by your field flattener, reducer, or coma corrector is critical for achieving sharp stars across the entire frame. This Baader 15mm M48 extension tube is a high-quality, fixed-length spacer designed to close a specific gap in your optical train, eliminating the flexure or tilt that can occur with variable-length adapters.

    The M48 thread (often called the 2-inch filter thread) provides a wider, unvignetted light path compared to the smaller T-2 (M42) standard, making this 15mm extension essential for imagers using full-frame or large APS-C sensors. It integrates seamlessly into the comprehensive Baader adapter system, allowing you to build a robust and precise imaging setup.

  • What is the Baader M48 15mm Extension Tube primarily used for?

    This extension tube is used to achieve a precise 15mm of additional back focus in an astrophotography imaging train. It is essential for connecting a camera to a field flattener, reducer, or off-axis guider at the exact distance required by the optics manufacturer for optimal performance.

    How do I know if I need a 15mm extension for my specific reducer?

    You must calculate the total back focus of your current setup. Start with the required back focus of your reducer (e.g., 55mm), then subtract the back focus of your camera and any other accessories (filter wheel, OAG). If the remaining distance is 15mm, this Baader M48 extension tube is the correct part.

    Will this 15mm M48 extension tube cause vignetting with my full-frame camera?

    No. The M48 thread standard is specifically designed to provide a large enough clear aperture to fully illuminate full-frame sensors (24x36mm) without vignetting. It is the preferred connection standard for serious imagers using large-format cameras to avoid darkening at the corners of the field.

    What is the difference between this M48 tube and a T-2 (M42) extension tube?

    The primary difference is the thread diameter. M48 (48mm) offers a wider clear aperture than T-2 (42mm). While T-2 is sufficient for smaller sensors, M48 is necessary to prevent vignetting on full-frame and large APS-C sensors, especially in fast optical systems.

    Can I stack this Baader 15mm extension tube with other M48 spacers?

    Yes, you can stack multiple Baader extension tubes to achieve a custom length (e.g., a 15mm and a 10mm tube for 25mm of spacing). Baader's precision machining ensures that stacked components remain parallel and secure, minimizing the risk of optical tilt.

    Why does Baader use a 3mm thread depth on this 15mm M48 extension?

    Modern astronomy cameras often have very short bodies and minimal flange distance. Baader's 3mm thread depth standard prevents the male threads of the extension tube from bottoming out inside the camera or accessory before the connection is tight. This ensures a secure, flush fit with contemporary equipment.

  • Extension Length 15mm
    Male Thread M48 x 0.75
    Female Thread M48 x 0.75
    Thread Depth 3mm
    Net weight (kg) 0.02
    Compatible Brands Baader Planetarium
    Clamping System no clamp
    Inner Diameter / Clear Aperture (mm) 45 mm
    Outer Diameter 53 mm
    Usage Adjusting the distances of accessories with M48 thread
    Outer Connection (eyepiece/-camera-sided) M48
    Inner Connection (lens sided) M48
    Adapters Family M48 System

    • Baader M48 Extension Tube - 15mm

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  • Baader Planetarium Warranty Policy