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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 O-III 1.25" Super-G Filter (9nm) - CMOS optimiert
Baader Planetarium O-III Super-G Filter (9nm) – CMOS-optimized
Baader Planetarium O-III Super-G Filter (9nm) – CMOS-optimized
Baader Planetarium Baader O-III 2" Super-G Filter - CMOS Optimized
Baader Planetarium O-III Super-G Filter (9nm) – CMOS-optimized
Baader Planetarium O-III Super-G Filter (9nm) – CMOS-optimized
Baader Planetarium O-III 1.25" Super-G Filter (9nm) - CMOS optimiert
Baader Planetarium Baader O-III 2" Super-G Filter - CMOS Optimized

Baader Planetarium O-III Super-G Filter (9nm) – CMOS-optimized

by Baader Planetarium
SKU BAA-2961550
$108.00 - $200.00
$108.00
$108.00 - $200.00
$108.00
Price Match Policy!
  • 9nm O-III Narrowband Passband
  • Functions as a "Super-G" Green Filter Replacement
  • CMOS-Optimized Coatings for High Contrast
  • Reduces Impact of Atmospheric Seeing
  • Available in 1.25" (M28.5 Thread) and 2" (M48 Thread) Filter Cells
1 in stock
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  • Description
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  • Baader O-III Super-G Filter (9nm) – CMOS-optimized

    The Baader O-III Super-G Filter redefines green channel astrophotography by replacing a standard broadband green filter with a targeted 9nm passband. This innovative approach uses the Oxygen-III emission line to capture sharper, higher-contrast data, especially on nights with poor atmospheric seeing, and is available in standard 1.25" (M28.5 thread) and 2" (M48 thread) cells to fit your filter wheel.

    The 9nm "Super-G" Filter: Sharper Green Channel Data in Poor Seeing

    Instead of using a traditional broadband green filter that is highly susceptible to atmospheric turbulence, this filter leverages a narrow 9nm window around the O-III lines. This technique significantly darkens the sky background and passes less thermal noise, allowing you to cut through bad seeing for noticeably sharper stars and finer nebular detail in your G-channel data.

    While its 9nm bandpass is restrictive, it is wide enough to gather sufficient signal for use as a green-channel substitute, bridging the gap between broadband and pure narrowband imaging. For emission nebulae rich in Oxygen-III, this filter acts as a powerful contrast-booster, isolating the most important signal from the object itself.

    Baader 9nm O-III vs. a Standard Broadband Green Filter

    The choice between this O-III filter and a standard green filter depends entirely on your target and sky conditions. A traditional green filter is the better choice for broadband targets like galaxies, where you need to capture continuum emission across a wide spectral range.

    The Baader 9nm O-III filter's strength is revealed on emission nebulae or any time atmospheric seeing is the limiting factor. By rejecting the blurred wavelengths most affected by turbulence, it produces a sharper final image, even if the individual sub-exposures are slightly dimmer. On nights of poor seeing, the improved resolution from the 9nm O-III filter will deliver a superior LRGB result.

    1.25" (M28.5) and 2" (M48) Formats with CMOS-Optimized Design

    Engineered for modern astronomy, this filter is built into either a standard 1.25" cell with M28.5 threads or a standard 2" cell with M48 threads, for broad compatibility with filter wheels, filter drawers, and eyepiece holders of each format. The optical surfaces feature Baader's latest CMOS-optimized coating technology, which delivers critical benefits for today's sensitive cameras.

    • Steep Passband Slopes: Advanced coatings create extremely sharp transitions between transmitted and blocked wavelengths. This increases contrast and ensures that only the desired 9nm O-III window reaches the sensor.
    • Reflection Suppression: The coatings are designed to eliminate the reflections and halos that can occur between the filter and a CMOS sensor, ensuring clean data even with bright stars in the field.
    • Enhanced Durability: These hard, resilient coatings protect the filter from the elements and allow for safe, repeated cleaning without degradation.

  • What is the main purpose of the Baader O-III 9nm Super-G filter?

    Its primary purpose is to act as a high-performance substitute for a standard broadband green (G) filter in an LRGB imaging sequence. By using a narrow 9nm passband, it cuts through atmospheric turbulence (seeing) to produce a much sharper green channel, especially on nights with poor conditions.

    How does this Baader 9nm O-III filter improve sharpness over a regular green filter?

    Atmospheric seeing blurs starlight across a wide range of wavelengths. A standard green filter passes this entire blurred signal. The 9nm O-III filter rejects most of this turbulent energy, passing only a very narrow slice of the spectrum, which results in a tighter, sharper image at the expense of some brightness.

    Is the Baader O-III 9nm filter a true narrowband filter?

    It's best described as a hybrid. While much narrower than a broadband filter, its 9nm passband is wider than typical "ultra-narrowband" filters (which are often 3-7nm). This makes it narrow enough to beat seeing but wide enough to gather enough signal to effectively serve as a replacement for the green channel in LRGB imaging.

    When imaging the Dumbbell Nebula (M27) with a CMOS camera, should I use this 9nm O-III filter or a standard green filter?

    For the Dumbbell Nebula (M27), which is extremely rich in Oxygen-III, the Baader 9nm O-III filter is the superior choice. It will dramatically increase the contrast of the nebula against the sky background and provide a sharper G-channel signal than a standard green filter would, especially if seeing is less than perfect.

    Can I use the Baader 9nm O-III filter for visual observing with my 8" SCT?

    Yes, absolutely. As a visual O-III filter, it performs very well. In an 8" SCT, it will significantly enhance the contrast of emission nebulae like the Orion Nebula (M42) or the Veil Nebula (NGC 6960), making them stand out against the background sky. The 9nm bandpass provides a nice balance between contrast enhancement and image brightness.

    Which size of the Baader O-III Super-G filter fits my filter wheel?

    Choose the size that matches your filter wheel or holder. The 1.25" version sits in a standard cell with an M28.5 x 0.6 thread for 1.25" filter wheels, drawers and eyepiece holders, while the 2" version uses a standard cell with an M48 x 0.75 thread, making it compatible with virtually all 2-inch filter wheels, filter drawers and eyepiece holders. Both sizes feature the same CMOS-optimized coatings that suppress halos and reflections.

  • 1.25" Round Mounted

    Filter Type O-III "Super-G"
    Bandwidth 9 nm
    Size 1.25"
    Filter Thread M28.5 x 0.6
    Coatings CMOS-Optimized, Anti-Reflection

    2" Round Mounted

    Filter Type O-III "Super-G"
    Primary Use RGB Imaging Green Channel Replacement
    Coatings CMOS-Optimized, Anti-Reflective
    Passband Narrowband (Hybrid)
    Size 2" Mounted
    Threads M48 x 0.75

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