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Baader T-2 Extension Tube- 40mm
Baader T-2 Extension Tube- 40mm
Baader T-2 Extension Tube- 40mm

Baader T-2 Extension Tube- 40mm

by Baader Planetarium
SKU BAA-1508153
CA$40.00 - CA$40.00
CA$40.00
CA$40.00 - CA$40.00
CA$40.00
Price Match Policy!
  • Adds exactly 40mm of optical path length
  • Standard T-2 (M42x0.75) male and female threads
  • Provides rigid, non-flexing spacing for astrophotography
  • Machined for the Baader Astro T-2 System
1 in stock
Qualifies for FREE Shipping in Canada on orders over $500.
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Baader T-2 Extension Tube- 40mm

    The Baader T-2 Extension Tube adds exactly 40mm of length to any T-2 threaded (M42x0.75) optical train. This fixed 40mm length is a fundamental building block for achieving the critical sensor-to-corrector distance required by many popular coma correctors, field flatteners, and reducers.

    Precise 40mm Spacing for T-2 Systems

    This component provides a fixed, rigid 40mm of separation, eliminating the potential for tilt or flex that can occur with less secure connections. As part of the comprehensive Baader Astro T-2 System, it integrates seamlessly with a vast range of adapters, diagonals, and accessories, all sharing the universal M42x0.75 thread standard. This modularity allows you to construct a robust, threaded imaging train from your telescope to your camera sensor.

    When to Choose a 40mm T-2 Extension Tube

    A 40mm extension is a substantial spacer, often used to make up the majority of the common 55mm back focus requirement. While shorter tubes (like 7.5mm or 15mm) and fine-tuning rings are used for dialing in the final millimeter, the 40mm tube gets you most of the way there in one solid, stable component.

    • Back Focus Foundation: Use the 40mm tube as the primary spacer, then add a smaller extension or variable spacer to achieve perfect focus across the field.
    • Reaching Focus: It can also be used to push an eyepiece or camera further out from the focuser to reach focus on certain telescope designs, particularly in off-axis guider setups.
    • Rigidity Over Variability: For a permanent imaging setup where the spacing is known, a fixed tube like this 40mm extension provides greater stability than a variable or helical extension.

  • What is the main purpose of the Baader 40mm T-2 Extension Tube?

    Its primary purpose is to add a precise, fixed 40mm of distance within an astrophotography imaging train. This is crucial for setting the correct back focus distance between a camera sensor and an optical corrector like a field flattener or coma corrector, which is often a total of 55mm.

    How would I use the Baader 40mm T-2 tube to get 55mm of back focus from my corrector?

    You would thread the 40mm extension tube onto your corrector's T-2 threads. To achieve the remaining 15mm, you would typically add a 15mm T-2 extension tube or use a combination of other spacers (e.g., a 10mm and a 5mm tube) to reach the exact 55mm distance required for sharp stars across your camera's sensor.

    Are the T-2 threads on the Baader 40mm tube compatible with my ZWO or QHY astronomy camera?

    Yes. T-2 threads, which are technically M42x0.75, are the industry standard for most dedicated astronomy cameras, including those from ZWO, QHY, and others. This Baader extension tube will thread directly onto the camera body or any T-2 accessories they come with.

    Why should I use a fixed 40mm Baader tube instead of a variable T-2 extension?

    A fixed extension tube offers superior rigidity and stability. Variable or helical extenders can introduce a small amount of tilt or flex, especially with heavier cameras, which can degrade image quality. For a permanent or semi-permanent setup where the 40mm distance is known, a fixed tube is the more robust solution.

    Does the Baader 40mm T-2 Extension Tube have anti-reflection blackening inside?

    Yes. Baader Planetarium T-2 components are known for their high-quality, matte black internal surfaces. This design feature helps to absorb stray light within the optical path, maximizing contrast and preventing reflections from degrading your images.

    Can I stack multiple Baader 40mm T-2 Extension Tubes for a longer distance?

    Absolutely. You can thread multiple T-2 extension tubes together to create longer custom lengths. For example, two 40mm tubes would create a rigid 80mm extension. The precision machining ensures a secure and aligned connection when stacking.

  • Extension Length 40mm
    Male Thread T-2 (M42x0.75)
    Female Thread T-2 (M42x0.75)
    System Baader Astro T-2 System
    Net weight (kg) 0.04
    Inner Diameter / Clear Aperture (mm) 38
    Outer Diameter 46
    Usage for eyepiece projection with sliding focuser

    • Baader T-2 Extension Tube (40mm)

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  • Baader Planetarium Warranty