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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.
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 Baader H-alpha 1.25" f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 2" f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 31mm f/3 Ultra-Highspeed-Filter (3.5nm)
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 31mm f/3 Ultra-Highspeed-Filter (3.5nm)
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 31mm f/3 Ultra-Highspeed-Filter (3.5nm)
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 50x50mm f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha 65x65mm f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 1.25" f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 2" f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 31mm f/3 Ultra-Highspeed-Filter (3.5nm)
Baader Planetarium Baader H-alpha 31mm f/3 Ultra-Highspeed-Filter (3.5nm)
Baader Planetarium Baader H-alpha 31mm f/3 Ultra-Highspeed-Filter (3.5nm)
Baader Planetarium Baader H-alpha 50x50mm f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha 65x65mm f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized

Baader Planetarium H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized

by Baader Planetarium
SKU BAA-2961350
$347.00 - $770.00
$347.00
$347.00 - $770.00
$347.00
Price Match Policy!
  • 3.5nm H-alpha Bandpass
  • Optimized for f/3 Ultra-High-Speed Systems
  • Available in 1.25" & 2" mounted, 31mm, 36mm & 50.4mm round unmounted, and 50x50mm & 65x65mm square sizes
  • CMOS-Optimized Anti-Reflection and Anti-Halo Coatings
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Baader H-alpha f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized

    The Baader H-alpha f/3 Ultra-Highspeed-Filter is specifically engineered for modern astrographs, delivering the full contrast of its tight 3.5nm bandpass on optical systems down to f/3. Offered in mounted 1.25" (M28.5x0.6) and 2" cells, as unmounted 31mm, 36mm and 50.4mm round filters, and as 50x50mm or 65x65mm squares, it uses a pre-shifted design to ensure the critical H-alpha emission line is not lost to bandpass shift, a common failure point for conventional narrowband filters on fast scopes.

    Optimized for f/3 Optics: Maximizing Signal on Fast Telescopes

    Standard narrowband filters are designed for slower telescopes. When used on a fast f/3 system, the steep light cone causes a "blue shift" in the filter's bandpass, moving it away from the H-alpha wavelength and causing significant signal loss. Baader's f/3 Ultra-Highspeed filter is pre-shifted to be perfectly on-band at these fast focal ratios, ensuring maximum signal capture from emission nebulae.

    3.5nm Bandpass: Extreme Contrast on H-alpha Targets

    With a narrow 3.5nm bandpass, this filter dramatically increases contrast by rejecting unwanted light from moonlight, artificial light pollution, and natural skyglow. This isolates the H-alpha signal, darkening the sky background and making faint nebulosity stand out. The narrow window also tightens stars by blocking more of their continuum spectrum, preventing bloat on long exposures.

    CMOS-Optimized Coatings for High-Reflectivity Sensors

    Modern CMOS sensors are highly reflective, which can create halos and internal reflections when paired with traditional filters. This Baader filter features advanced coatings specifically designed to be "CMOS-optimized." These coatings suppress reflections between the filter and the sensor, eliminating artifacts around bright stars and preserving the clean, high-contrast background your fast optics can deliver. The unmounted 31mm size suits filter wheels for APS-C or smaller sensors, 36mm fits standard wheels for larger chips, and the 50.4mm round and 50x50mm or 65x65mm square formats illuminate full-frame and larger sensors without vignetting.

    High-Speed f/3 vs. Conventional f/10 Filters: The Critical Difference

    Choosing the right filter for your telescope's focal ratio is essential for narrowband imaging. While a conventional filter is a great choice for a slower instrument, it becomes a bottleneck on a fast system.

    • Conventional f/10 Filter: On slower telescopes, these filters perform exactly as specified. However, at f/3, their bandpass shifts so far that a significant portion of the H-alpha light you're trying to capture is blocked.
    • Baader f/3 High-Speed Filter: This filter is purpose-built for the steep light cones of f/3 systems. Its pre-shifted bandpass ensures that the peak H-alpha transmission aligns perfectly with your fast optics, resulting in brighter, higher-signal images in less time.

  • What makes the Baader f/3 H-alpha filter different from a standard 3.5nm filter?

    A standard 3.5nm filter is designed for slower telescopes. The Baader f/3 Ultra-Highspeed filter is "pre-shifted," meaning its bandpass is centered correctly for the steep light cone of an f/3 optical system. This prevents the signal loss that occurs when using a conventional filter on a fast telescope like a RASA or HyperStar.

    How will the Baader 3.5nm f/3 H-alpha filter perform on my Celestron RASA or HyperStar system?

    A Celestron RASA or a telescope with a Starizona HyperStar operates at a very fast focal ratio (around f/2 to f/3). The Baader f/3 H-alpha filter will perform far better than a standard filter on such systems, allowing you to capture deep, high-contrast images of emission nebulae like the North America Nebula (NGC 7000). It is optimized for systems around f/3; on systems faster than f/3, such as an f/2 RASA, some band-shift may remain, and Baader's f/2 Highspeed filter series is matched more precisely to that focal ratio.

    Can I use the Baader f/3 Ultra-Highspeed H-alpha filter on my f/8 refractor?

    It is not recommended. Because the filter is pre-shifted for f/3 systems, using it at f/8 will place the bandpass off the H-alpha line in the other direction, causing signal loss. For an f/8 telescope, a conventional narrowband filter designed for slower focal ratios is the better choice.

    Why is the Baader f/3 H-alpha filter "CMOS-optimized"?

    "CMOS-optimized" refers to the advanced anti-reflection coatings. Modern CMOS sensors have highly reflective surfaces that can cause halos and internal reflections with standard filters. The coatings on the Baader f/3 H-alpha filter are designed to suppress these reflections, resulting in cleaner images with fewer artifacts, especially around bright stars.

    Will the Baader 3.5nm f/3 H-alpha filter help me image the Horsehead Nebula (Barnard 33) from my light-polluted backyard?

    Yes, absolutely. The very narrow 3.5nm bandpass is extremely effective at blocking out broadband light pollution. By isolating just the H-alpha light from the nebula behind the Horsehead, this filter will dramatically increase the contrast of your image, making it possible to capture faint details even from urban or suburban locations.

    Do I need longer exposures with this 3.5nm Baader f/3 H-alpha filter compared to a 7nm filter?

    All else being equal, a 3.5nm filter passes half the light of a 7nm filter and would typically require longer exposures. However, this filter is designed for ultra-fast f/3 systems which gather light much more quickly than slower scopes. The extreme light-gathering power of the telescope compensates for the narrower bandpass, allowing you to capture deep data efficiently.

  • Single or Set? Single Filter
    Filter Usage CMOS, CCD, H-alpha
    CWL (Central Wavelength) 656.3 nm
    Suitable for f/ratio f/3.4 to f/2.3

    1.25" Round Mounted

    Filter Type H-alpha Narrowband
    Size 1.25"
    Bandpass 3.5nm
    Optimized Focal Ratio f/3
    Sensor Compatibility CMOS-optimized
    Net weight (kg) 0.01
    Filter size 1.25 inch
    Filter shape round
    Filter mounted Mounted (LPFC 6mm)
    Filter Thickness (without cell) 2 mm
    AR-Coating Reflex-Blocker™ hard coated, planeoptically polished

    2" Round Mounted

    Filter Type H-alpha Narrowband
    Bandwidth 3.5nm
    Size 2" (Mounted)
    Optimized Focal Ratio f/3
    Sensor Compatibility CMOS-Optimized
    Net weight (kg) 0.01
    Filter shape round
    Filter mounted Mounted (LPFC 6mm)
    Filter Thickness (without cell) 2 mm
    AR-Coating Reflex-Blocker™ hard coated, planeoptically polished

    31mm Round Unmounted Filter

    Filter Type H-alpha Narrowband
    Bandwidth 3.5nm
    Size 31mm, Unmounted
    Recommended Focal Ratio f/3
    Sensor Compatibility CMOS-Optimized
    Net weight (kg) 0.01 (50.4mm)
    Filter size 31 mm (31mm)
    36 mm (36mm)
    50.4 mm (50.4mm)
    Filter shape round
    Filter Thickness (without cell) 2 mm (31mm, 36mm)
    3 mm (50.4mm)
    AR-Coating Reflex-Blocker™ hard coated, planeoptically polished

    36mm Round Unmounted Filter

    Filter Type H-alpha Narrowband
    Bandwidth 3.5nm
    Size 36mm, Unmounted
    Optimized Focal Ratio f/3
    Series Ultra-Highspeed
    Sensor Compatibility CMOS-Optimized
    Net weight (kg) 0.01 (50.4mm)
    Filter size 31 mm (31mm)
    36 mm (36mm)
    50.4 mm (50.4mm)
    Filter shape round
    Filter mounted Unmounted
    Type of Filter f/3 Ultra-Highspeed
    Filter Thickness (without cell) 2 mm (31mm, 36mm)
    3 mm (50.4mm)
    HBW (Halfbandwidth) 3.5 nm
    Transmission Range H-alpha
    AR-Coating Reflex-Blocker™ hard coated, planeoptically polished

    50.4mm Round Unmounted Filter

    Filter Type H-alpha Narrowband
    Bandwidth 3.5nm
    Size 50.4mm (unmounted)
    Optimized Focal Ratio f/3 to f/5
    Sensor Compatibility CMOS-optimized
    Coatings Reflex-Blocker™ Hard Coated
    Substrate Planeoptically Polished
    Net weight (kg) 0.01 (50.4mm)
    Filter size 31 mm (31mm)
    36 mm (36mm)
    50.4 mm (50.4mm)
    Filter shape round
    Filter Thickness (without cell) 2 mm (31mm, 36mm)
    3 mm (50.4mm)

    50x50mm Square Filter

    Filter Type H-alpha Narrowband
    Size 50x50 mm
    Format Unmounted Square
    Bandpass (FWHM) 3.5 nm
    Optimized Focal Ratio f/3
    Series Ultra-Highspeed
    Coatings CMOS-Optimized, Reflex-Blocker™, Life-Cal™
    Net weight (kg) 0.02
    Filter Thickness (without cell) 3 mm
    AR-Coating Reflex-Blocker™ hard coated, planeoptically polished

    65x65mm Square Filter

    Filter Type H-alpha, CMOS-Optimized
    Bandwidth (FWHM) 3.5nm
    Size 65mm x 65mm
    Format Unmounted Square
    Optimal Focal Ratio f/3 to f/3.5
    Coatings Reflex-Blocker™, Life-Coat™
    Net weight (kg) 0.03
    Filter size 65 x 65 mm
    Filter Thickness (without cell) 3 mm
    AR-Coating Reflex-Blocker™ hard coated, planeoptically polished

    • Baader H-alpha f/3 Ultra-Highspeed-Filter (3.5nm), selected size

      × 1

    • Filter Storage Case (2" mounted version)

      × 1

  • Baader Planetarium Warranty Policy