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Baader Planetarium Locking Ring T-2i – 4mm
Baader Planetarium Locking Ring T-2i – 4mm
Baader Planetarium Locking Ring T-2i – 4mm
Baader Planetarium Locking Ring T-2i – 4mm
Baader Planetarium Locking Ring T-2i – 4mm

Baader Planetarium Locking Ring T-2i – 4mm

by Baader Planetarium
SKU BAA-2408190A
CA$35.00 - CA$35.00
CA$35.00
CA$35.00 - CA$35.00
CA$35.00
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  • Provides 4mm of fixed spacing
  • Internal T-2 (female) threads
  • Locks rotational orientation of accessories
  • Thin profile for fine back-focus adjustments
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Locking Ring T-2i – 4mm

    The T-2i Locking Ring provides exactly 4mm of rigid spacing in any T-2 thread system, allowing for precise back focus adjustment and secure rotational locking of cameras, filter wheels, and other accessories.

    Achieve 4mm of Precise T-2 Spacing

    This T-2i locking ring is an essential component for fine-tuning your imaging train. Its primary function is to add a precise 4mm of distance, helping you achieve the critical back focus required by your flattener or reducer. It also solves the common problem of accessories ending up at an awkward angle when fully threaded in.

    By threading the ring onto a male T-2 thread first, you can then attach your camera or other accessory. Simply back the accessory off to the desired orientation and tighten the locking ring against it to hold it firmly in place. The "i" designates an internal (female) thread, making it compatible with the vast majority of T-2 male-threaded components.

  • What is the primary use for the 4mm T-2i Locking Ring?

    The 4mm T-2i Locking Ring serves two main purposes. First, it acts as a precision spacer, adding exactly 4mm to your optical train to meet back focus requirements. Second, it allows you to lock the rotational angle of an accessory, like a camera, so you can achieve perfect framing without the component unthreading.

    How does the T-2i Locking Ring help when attaching my ZWO camera to an off-axis guider?

    When you thread a camera into an off-axis guider (OAG), its final orientation can be random. The 4mm T-2i Locking Ring lets you back the camera off slightly to get the correct framing and then lock it securely in that position. It also contributes its 4mm thickness to the overall back focus distance, which must be factored into your calculations.

    Is the 'i' in T-2i significant for the 4mm Locking Ring?

    Yes. The 'i' stands for internal (female) thread. This means the 4mm Locking Ring threads onto an external (male) T-2 thread, which is the most common configuration needed for locking accessories against a telescope, flattener, or other component.

    Can I stack multiple 4mm T-2i Locking Rings to create more space?

    While you can physically stack them, it is not recommended for achieving larger spacing. For maximum rigidity and to avoid potential tilt in the optical path, it is always better to use a single, solid T-2 extension tube of the correct length (e.g., an 8mm or 10mm extender).

    Will the 4mm T-2i Locking Ring work with non-T-2 accessories?

    No, the 4mm T-2i Locking Ring is designed specifically for the T-2 thread standard (M42x0.75). It will not work with other common astronomy thread types like M48 (2-inch filter thread) or larger SCT threads unless you use the appropriate conversion adapters.

    I need to add 4mm of spacing to my Celestron SCT's focal reducer. Is the T-2i Locking Ring the right part?

    If your Celestron focal reducer terminates in a male T-2 thread, then the 4mm T-2i Locking Ring is a perfect way to add that precise distance to reach the required back focus for your camera. It provides a simple and rigid solution for this common scenario.

    • Locking Ring T-2i – 4mm

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