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Baader Double T-Filterholder - 1.25"

Baader Double T-Filterholder - 1.25"

by Baader Planetarium
SKU BAA-1508030
CA$49.00 - CA$49.00
CA$49.00
CA$49.00 - CA$49.00
CA$49.00
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  • Holds two standard 1.25" filters
  • Enables rapid switching between filters
  • T-2 (M42x0.75) threads on both sides
  • Minimal back focus consumption
  • Ideal for visual comparison or simple imaging sequences
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Baader Double T-Filterholder - 1.25"

    The Baader Double T-Filterholder provides a simple, robust solution for instantly switching between two standard 1¼" (1.25") filters without altering your imaging or visual train. This component is engineered for observers and imagers who need to perform direct A/B comparisons or execute simple two-filter sequences with maximum speed and minimal complexity.

    Instant A/B Comparison for Two 1.25" Filters

    The core function of this holder is to place two 1.25" filters side-by-side in a sliding mechanism. This allows you to move from one filter to the other in less than a second, providing a near-instantaneous comparison that is impossible to achieve by manually unthreading filters in the dark.

    For visual observers, this is invaluable for determining the ideal filter for a specific nebula under current sky conditions—for example, switching between an O-III and a UHC filter on the Veil Nebula (NGC 6960). For planetary imagers, it enables rapid sequences, such as capturing a luminance channel followed immediately by a color or IR-pass filter, minimizing the impact of atmospheric turbulence between captures.

    T-2 System Integration for a Secure, Low-Profile Connection

    Designed as part of the Baader T-2 Astro System, the Double T-Filterholder features standard T-2 (M42x0.75) female threads on one side and male threads on the other. This ensures direct, secure integration into virtually any established imaging train, connecting between a camera nosepiece, off-axis guider, or focal reducer without flexure.

    Its slim profile is engineered to consume minimal back focus, making it a viable option for optical systems with tight spacing requirements, such as those using coma correctors or reducers. The all-metal construction ensures rigidity and precise alignment of the optical axis.

    Baader Double Filter Holder vs. a Filter Wheel: Simplicity vs. Capacity

    While a motorized filter wheel offers automated access to five or more filters, the Baader Double T-Filterholder serves a different purpose focused on speed and simplicity. It is an excellent choice when your workflow only requires two filters and you want to avoid the weight, power requirements, and software complexity of a full filter wheel.

    • Choose the Double Holder if: Your primary goal is quick visual comparison, you image with a monochrome camera and a single filter (e.g., L+Ha), or you prioritize a lightweight, manual, and travel-friendly setup.
    • Choose a Filter Wheel if: You need to perform automated LRGB or narrowband sequences, require more than two filters for a session, and are operating within a fully software-controlled imaging rig.

  • How can the Baader Double T-Filterholder improve my views of the Orion Nebula (M42)?

    You can install two different nebula filters, such as a broadband UHC filter and a narrowband O-III filter. The UHC will reveal the full extent of the nebula's faint outer loops, while a quick slide to the O-III filter will dramatically increase contrast in the bright core around the Trapezium. This lets you study different structures within M42 in real-time without interrupting your observation.

    Is the Baader Double T-Filterholder practical for planetary imaging with a monochrome camera?

    Yes, it is highly effective. You can mount a Luminance (IR-Cut) filter in one slot and an IR-Pass filter in the other. This allows you to capture a sharp, high-detail luminance channel and then immediately switch to the IR-pass filter, which helps stabilize the image in turbulent seeing, all without refocusing or disassembling your camera setup.

    What threads does the Baader Double T-Filterholder use for connection?

    The holder uses the standard T-2 thread system, which is M42x0.75. It has female T-2 threads on the telescope side and male T-2 threads on the camera side, allowing it to be inserted directly into common imaging trains.

    Will this 1.25" filter holder cause vignetting with my camera?

    With cameras that have small to medium sensors (up to approximately APS-C size, depending on the telescope's focal ratio), vignetting is typically not an issue. However, with full-frame (24x36mm) sensors, a 1.25" filter will almost always cause significant vignetting. For full-frame sensors, a 2-inch filter solution is recommended.

    Is the Baader Double T-Filterholder difficult to use in the dark?

    No, it is designed for tactile use. The slider has a distinct stop at each filter position, so you can feel when it is correctly aligned without needing to look. This makes it very easy to switch between filters even on the darkest nights.

    Can I use 2" filters with the Baader Double T-Filterholder?

    No, this model is designed exclusively for standard 1.25" (M28.5 thread) filters. Baader Planetarium offers different solutions for 2" filters.

  • Net weight (kg) 0.01
    Compatible Brands Astro T-2, Baader Planetarium, Celestron
    Inner Diameter / Clear Aperture (mm) 28
    Outer Diameter 46
    Type of Adapter Filter holder, Same-Thread Adapter
    T-2 Part # 31
    Inner Connection (eyepiece/-camera-sided) M28.5
    Outer Connection (eyepiece/-camera-sided) M42 x 0.75 (T-2)
    Inner Connection (lens sided) M28.5
    Outer Connection (lens sided) M42 x 0.75 (T-2)
    Adaptable to SBIG CCD-Cameras, CFW-8 color filter wheel
    Adapters Family T-2 System
  • Baader Planetarium Warranty