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Baader UFC AUX Filter-Holder - D 31mm (requires UFC-RD50)
The Baader UFC AUX Filter-Holder is designed to secure a 31mm unmounted filter inside the Baader UFC-RD50 Filter Slider (#2459113). This component is a specialized adapter that enables dual-filter configurations within a single optical path, adding significant flexibility to the Baader Universal Filter Changer (UFC) system.
For the UFC-RD50 Slider: Integrating a 31mm Filter
This holder does not function as a standalone component; it is engineered exclusively to nest inside the larger UFC-RD50 filter slider. The RD50 slider is intended for 50.4mm round filters, and this AUX holder allows you to securely mount a smaller, 31mm unmounted filter within that same slider, expanding its capabilities beyond its primary format.
Dual-Filter Imaging: Stacking Filters in a Single Path
The primary application for the UFC AUX 31mm holder is to stack two filters in the optical path. This is particularly useful for imagers who wish to combine a 31mm filter, such as a UV/IR cut or a specific narrowband filter, with a primary 50.4mm filter housed in the main slot of the UFC-RD50 slider. This configuration allows for advanced imaging techniques without the need for a second filter wheel or slider.
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What is the purpose of the Baader UFC AUX Filter-Holder for 31mm filters?
Its sole purpose is to allow you to mount a 31mm unmounted filter inside of a Baader UFC-RD50 Filter Slider. This enables you to use smaller filters or create stacked filter combinations within the larger Baader UFC system.
Can I use the 31mm UFC AUX Filter-Holder without the UFC-RD50 slider?
No. This holder is not a standalone part and has no threads of its own. It is designed specifically to fit inside the machined receptacle of the Baader UFC-RD50 Filter Slider (#2459113) and cannot be used with any other component.
Does the UFC AUX holder work with mounted 1.25" filters?
No. This holder is precisely machined for 31mm unmounted glass filters only. Standard 1.25" filters are housed in threaded cells and will not fit.
How would I use the UFC AUX 31mm holder when imaging the Rosette Nebula (NGC 2244) with a monochrome camera?
A common technique is to place a 31mm unmounted UV/IR Cut filter in this AUX holder. You would then place your primary 50.4mm H-alpha filter in the main slot of the UFC-RD50 slider. This stack ensures clean, high-contrast data by capturing the nebula's specific emission line while blocking unfocused infrared light.
I use a one-shot-color camera with an f/5 Newtonian. Can I use the UFC AUX 31mm holder to add a light pollution filter?
Yes, this is an excellent use case. If you have a 31mm unmounted light pollution filter (such as a UHC or multi-bandpass filter), you can install it in this holder within your UFC-RD50 slider. This allows you to add powerful light pollution suppression to your imaging train without needing to purchase a larger, more expensive 50mm filter.
Where does the UFC AUX 31mm holder fit into the overall Baader UFC system?
Think of it as an accessory for an accessory. It fits inside the UFC-RD50 slider, which in turn slides into the main UFC Base (#2459110). It is a modular component designed to add another layer of filtering flexibility to your existing UFC setup.
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| Filter Size |
31mm, Unmounted |
| Compatibility |
Requires Baader UFC-RD50 Filter Slider (#2459113) |
| Net weight (kg) |
0.01 |
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This product listing is for the UFC AUX Filter-Holder only. Required components are sold separately.
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Baader Planetarium Warranty Policy
