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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.
Baader Planetarium M54 Extension Tube – 40 mm
Baader Planetarium M54 Extension Tube – 40 mm
Baader Planetarium M54 Extension Tube – 40 mm

Baader Planetarium M54 Extension Tube – 40 mm

by Baader Planetarium
SKU BAA-2958740
$59.00 - $59.00
$59.00
$59.00 - $59.00
$59.00
Price Match Policy!
  • Provides 40mm of fixed extension
  • Standard M54 x 0.75 threads
  • Male and female threads for easy integration
  • Rigid design prevents flexure in the imaging train
1 in stock
Qualifies for FREE Shipping in CONUS on orders over $350.
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • M54 Extension Tube – 40 mm

    This M54 Extension Tube provides a fixed, non-flexing 40mm of spacing, essential for setting the correct back focus in a threaded imaging train. Designed for M54 accessories, it ensures your flattener or reducer is positioned at the precise distance required for a flat field from edge to edge.

    Achieve Precise 40mm Back Focus with M54 Threads

    Achieving the manufacturer-specified back focus is critical for astrophotography, and this 40mm extension tube is a simple, rigid solution for hitting that mark. It features male M54 threads on one side and female on the other, allowing it to connect seamlessly between your camera, filter wheel, or off-axis guider.

    The M54 thread standard provides a large, robust connection that prevents both vignetting on larger sensors and flexure that can tilt your camera sensor. This single 40mm tube is often a more stable solution than stacking multiple smaller extensions, which can introduce potential points of tilt or rotation.

  • What is the M54 Extension Tube – 40 mm primarily used for?

    This extension tube is used to add exactly 40mm of length to an M54-threaded imaging train. Its primary purpose is to help achieve the precise back focus distance required by optical correctors like field flatteners and focal reducers, ensuring sharp stars across the entire sensor.

    How do I know if I need a 40mm extension for my imaging setup?

    You need to calculate the total back focus required by your flattener or reducer (typically 55mm, but check your specific model) and then subtract the back focus consumed by your camera, off-axis guider, and filter wheel. If the remaining distance needed is 40mm, this extension is the correct component.

    Are the threads on this 40mm M54 tube male or female?

    Like most extension tubes, this component has male M54 threads on one end and female M54 threads on the other. This allows it to be inserted between two other M54 accessories, such as connecting a flattener to a filter wheel.

    Can I stack this 40mm M54 tube with other extensions?

    Yes, you can stack this with other M54 extensions to achieve a custom length. However, for maximum stability and to minimize potential tilt, it is always best to use a single extension tube that is as close as possible to your required distance.

    Will this 40mm M54 extension cause vignetting with my full-frame camera?

    No. The M54 standard (54mm diameter) is specifically designed to provide a large, unvignetted light path for full-frame sensors (42mm diagonal) and even some larger formats. This extension will not be the limiting factor for illumination in a properly designed full-frame imaging train.

    What is the thread pitch of the M54 threads on this 40mm extension?

    While not specified, the standard thread pitch for M54 accessories in astronomy is 0.75mm (M54x0.75). This extension is designed to be compatible with equipment from major brands that use this common standard.

  • Length 40 mm
    Thread Type M54 x 0.75
  • Baader Planetarium 2-Year Warranty