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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" Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 2" Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 31mm Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 31mm Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 31mm Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 50x50mm Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 65x65mm Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 1.25" Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 2" Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 31mm Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 31mm Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 31mm Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 50x50mm Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
Baader Planetarium Baader H-alpha 65x65mm Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized

Baader Planetarium H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized

par Baader Planetarium
UGC BAA-2961325
$352.00 - $795.00
$352.00
$352.00 - $795.00
$352.00
Égalisation de prix!
  • 3.5nm Ultra-Narrow Bandpass
  • Available in 1.25" & 2" mounted, 31mm, 36mm & 50.4mm round unmounted, and 50x50mm & 65x65mm square sizes
  • CMOS-Optimized Coatings to Suppress Halos
  • Isolates Hydrogen-Alpha Emission Lines
  • For Deep-Sky Astrophotography Only
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Baader H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized

    The Baader H-alpha Ultra-Narrowband Filter uses an extremely tight 3.5nm bandpass to isolate the critical 656.3nm wavelength of hydrogen-alpha light for maximum-contrast deep-sky imaging. This CMOS-optimized design is specifically engineered to eliminate the internal reflections and halos that can affect modern, highly sensitive sensors when imaging star-filled nebulae.

    The 3.5nm Bandpass: Maximum Contrast on H-II Regions

    By restricting the incoming light to a mere 3.5nm window, this filter dramatically increases the contrast between hydrogen-rich emission nebulae and the background sky. It effectively darkens light pollution and moonlight, allowing the faint, glowing structures of targets like the North American Nebula (NGC 7000) or the Heart Nebula (IC 1805) to dominate the image.

    Compared to wider 7nm or 12nm filters, the 3.5nm bandpass provides a significant boost in signal-to-noise ratio, revealing finer details and fainter extensions in H-II regions. This makes it an essential tool for imagers working from suburban or city locations, though it requires longer exposure times to compensate for the narrower window.

    CMOS-Optimized in Every Format: Halos and Reflections Suppressed

    Modern CMOS sensors are highly reflective, often causing halos and glare around bright stars when used with traditional filters. Baader's CMOS-optimized filters feature advanced anti-reflection coatings and blackened edges to mitigate these effects, ensuring clean data even on targets with high dynamic range, such as the Orion Nebula (M42) or the Sadr region in Cygnus.

    Choose the format that matches your imaging train: the 1.25" and 2" mounted filters fit filter wheels and drawers designed for those standard sizes, the unmounted 31mm and 36mm filters suit modern filter wheels that accept them, and the 50.4mm round and 50x50mm or 65x65mm square formats illuminate large sensors, up to full-frame and beyond, without vignetting. This allows for easy integration into your existing imaging train for both mono and one-shot-color camera setups.

    A 3.5nm Warning: Not Safe for Direct Solar Viewing

    This is a deep-sky filter and is absolutely not designed for any form of solar observation. The 3.5nm (equivalent to 35 Ångström) bandpass is dangerously wide for viewing the Sun. Professional solar filters, such as those from SolarSpectrum, have bandpasses under 1 Ångström—orders of magnitude narrower and safer.

    Never look at the Sun through this filter, either with a camera or visually, without a proper, full-aperture solar filter placed on the front of your telescope. Attempting to do so will cause immediate and permanent eye damage. As Baader explicitly states: you endanger your eyesight!

  • What is the advantage of the Baader 3.5nm H-alpha filter over a 7nm version?

    The primary advantage is higher contrast. The tighter 3.5nm bandpass more effectively rejects light pollution, moonlight, and continuum emission from stars. This results in a darker sky background and makes faint nebulosity stand out more clearly, especially from light-polluted locations.

    Can I use this Baader 3.5nm H-alpha filter for observing the Sun?

    Absolutely not. This is a deep-sky filter and is unsafe for solar observation. Its 3.5nm (35 Ångström) bandpass is far too wide and does not block enough of the Sun's energy. Using it for solar viewing without a dedicated, front-mounted solar filter will cause permanent blindness.

    Is the Baader 3.5nm H-alpha filter suitable for my color CMOS camera?

    Yes, this filter works exceptionally well with color CMOS cameras. By isolating only the deep red H-alpha wavelength, it allows you to capture high-contrast hydrogen data. This data can then be blended with a standard RGB image to dramatically enhance the red nebulosity in targets like the Andromeda Galaxy (M31) or the Rosette Nebula (NGC 2244).

    How will this Baader 3.5nm filter perform on the Orion Nebula (M42) from my city backyard?

    It will perform exceptionally well. From a city, the 3.5nm bandpass will reject a significant amount of skyglow, allowing you to capture the intricate details within the Orion Nebula (M42) that would otherwise be washed out. Its CMOS-optimized design will also help control the intense glare from the Trapezium stars at the nebula's core, preventing them from blowing out the delicate surrounding structure.

    Why is a "CMOS-optimized" filter important for my ZWO ASI or QHY camera?

    Modern astronomy cameras from ZWO, QHY, and others use highly reflective CMOS sensors. Standard filters can create internal reflections between the sensor and the filter glass, causing halos around bright stars. The CMOS-optimized coatings on this Baader filter are designed to suppress these reflections, leading to cleaner star shapes and higher-quality data.

    Which size of the Baader 3.5nm H-alpha filter fits my filter wheel or drawer?

    The mounted 1.25" version is the most common size and fits any 1.25" filter wheel, filter drawer, or eyepiece that accepts threaded filters; the mounted 2" version fits standard 2" filter wheels and drawers. The unmounted 31mm and 36mm filters need a filter wheel or carousel that specifically accepts that size and will not fit a threaded cell. The unmounted 50.4mm round filter suits larger filter wheels for APS-C or full-frame cameras, while the 50x50mm and 65x65mm squares require a filter wheel, slider or holder designed for that square format and cover full-frame and larger sensors.

  • 1.25" Round Mounted

    Filter Type H-alpha Ultra-Narrowband
    Bandpass 3.5nm
    Size 1.25" Mounted
    Sensor Compatibility CMOS-optimized
    Primary Use Deep-Sky Astrophotography
    Solar Safe No

    2" Round Mounted

    Filter Size 2"
    Bandwidth 3.5nm
    Spectral Line H-alpha (656.3nm)
    Primary Use Deep-Sky Astrophotography
    Sensor Compatibility Optimized for CMOS Sensors

    31mm Round Unmounted Filter

    Filter Type H-alpha Ultra-Narrowband
    Bandpass (FWHM) 3.5nm
    Central Wavelength 656.3 nm
    Size 31mm (Unmounted)
    Sensor Compatibility CMOS-optimized
    Coatings Reflex-Blocker™ hard coated, planeoptically polished
    Primary Use Deep-Sky Astrophotography
    Solar Safe No

    36mm Round Unmounted Filter

    Filter Type H-alpha Ultra-Narrowband
    Bandpass (FWHM) 3.5nm
    Size 36mm (Unmounted)
    Primary Application Deep-Sky Astrophotography
    Sensor Optimization CMOS
    Solar Safe No - For Nighttime Use Only

    50.4mm Round Unmounted Filter

    Filter Type H-alpha Ultra-Narrowband
    Bandpass (FWHM) 3.5nm
    Central Wavelength 656.3 nm
    Size 50.4mm (Unmounted)
    Sensor Compatibility CMOS-optimized
    Primary Use Deep-Sky Astrophotography
    Solar Safe No - Do Not Use for Solar Viewing

    50x50mm Square Filter

    Filter Type H-alpha Ultra-Narrowband
    Bandpass 3.5nm
    Size 50mm x 50mm
    Mounting Unmounted
    Primary Use Deep-Sky Astrophotography
    Sensor Compatibility CMOS-optimized

    65x65mm Square Filter

    Filter Type H-alpha Ultra-Narrowband
    Bandpass (FWHM) 3.5nm
    Size 65mm x 65mm
    Format Unmounted Square
    Coatings CMOS-Optimized
    Primary Use Deep-Sky Astrophotography
    Solar Safe No - Unsafe for Solar Observation

    • Baader H-alpha Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized, selected size

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  • Baader Planetarium Warranty