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Dual / Multi-Band Filters (Color)

A dual-band filter passes two narrow emission lines at once, usually hydrogen-alpha and oxygen III, and blocks almost everything else. With a colour camera, the red pixels record H-alpha and the green and blue pixels record OIII, so you get narrowband contrast in a single exposure, without a mono camera or filter wheel. It is the biggest single upgrade for a colour camera under city or suburban skies.

We carry Optolong L-Enhance, L-Extreme, L-Ultimate, L-Synergy, L-Para and L-Quad Enhance, Antlia ALP-T, Askar Colour Magic, SVBONY SV220, Player One Anti-Halo PRO and others, in 1.25-inch, 2-inch and smart telescope formats.

Filters

CA$554.00 - CA$554.00
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Antlia ALP-T Dual Band Ha&OIII 3nm

Passes H-alpha (656.3nm) and OIII (500.7nm) emission lines 3nm (+0.6/-0.1nm) FWHM on both lines Peak transmission of 90% (H-alpha) and 82% (OIII) ...

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CA$1,008.00 - CA$1,008.00
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CA$1,008.00

Antlia ALP-T Dual Band Ha&OIII 3nm + SII&Hb 3.5nm 2" Filter Set

Two dual-band filters for four narrowband channels with color cameras; also usable with mono cameras Ha & OIII Filter: 3nm FWHM at 656.3nm and...

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CA$511.00 - CA$511.00
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CA$511.00

Antlia ALP-T Dual Band SII&Hβ 3.5nm

Dual-band filter passing Sulfur-II (672.4nm) and Hydrogen-beta (486.1nm) 3.5nm (+/-0.5nm) FWHM on both lines Peak transmission of 90% (SII) and 85...

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CA$980.00 - CA$980.00
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CA$980.00

Antlia ALP-T Dualband 5nm Ha/OIII and SII/Hb Filter Set - 2"

2-filter set captures four narrowband channels (Ha, OIII, SII, H-beta) with one-shot color cameras Ha/OIII filter isolates H-alpha (656.3nm) and O...

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CA$540.00 - CA$540.00
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Antlia ALP-T Dualband 5nm Ha/OIII Filter

Dual line-pass filter for Hydrogen-alpha (656.3nm) and Oxygen III (500.7nm) Tight 5nm FWHM bandpass for both emission lines Peak transmission of 9...

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Antlia ALP-T Dualband 5nm Ha/OIII Highspeed Filter

Dual 5nm bandpasses for Hydrogen-alpha (657.8nm) and Oxygen-III (502.2nm) Optimized for high-speed imaging systems from f/2.2 to f/3.6 Peak transm...

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CA$497.00 - CA$497.00
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Antlia ALP-T Dualband 5nm SII/Hb Filter

Dual-bandpass 5nm design for one-shot color (OSC) cameras Passes Sulfur-II (672.4nm) and Hydrogen-Beta (486.1nm) emission lines Peak transmission ...

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CA$497.00 - CA$497.00
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Antlia S1 Dual-Band 5nm H-Alpha/OIII Filter for Seestar S50 Pro
Antlia S1 Dual-Band 5nm H-Alpha/OIII Filter for Seestar S50 Pro
CA$322.00 - CA$322.00
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CA$322.00

Antlia S1 Dual-Band 5nm H-Alpha/OIII Filter for Seestar S50 Pro

Designed specifically for the Seestar S50 Pro Dual-band filter passes H-alpha and OIII emission lines Narrow 5nm bandpass for high-contrast imagin...

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Askar 3nm Colour Magic Ha/OIII & SII/OIII (E1+E2) Filter Package

Enables SHO "Hubble Palette" imaging with a one-shot-color (OSC) camera Includes two ultra-narrow dual-bandpass filters: E1 (Hα+OIII) and E2 (SII+...

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CA$847.00 - CA$847.00
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Askar 3nm Colour Magic Ultra Ha/OIII E1 Filter - 2"

Dual-bandpass for Hydrogen-alpha (656.6nm) and Oxygen-III (500.7nm) Ultra-narrow 3.7nm (Ha) and 4.0nm (OIII) FWHM bandwidths 85% peak transmittanc...

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Askar 3nm Colour Magic Ultra OIII/SII E2 Filter - 2"

Dual-bandpass design captures OIII (500.7nm) and SII (672nm) simultaneously Narrow 3.7nm (OIII) and 4.0nm (SII) FWHM for high-contrast imaging Pea...

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Askar Colour Magic Ha/OIII & SII/OIII (C1+C2) Filter Package

Complete 2-Filter Narrowband Solution for Color Cameras Captures H-alpha, Oxygen-III, and Sulfur-II Wavelengths Filter 1 (C1): Hα + OIII Duo-Band ...

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Askar Colour Magic Ha/OIII C1 Filter - 2"

Dual-bandpass filter for H-alpha (656.6nm) and Oxygen-III (500.7nm) Asymmetrical bandwidths: 15nm for H-alpha, 35nm for OIII Greater than 90% peak...

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Askar Colour Magic SII/OIII C2 Filter - 2"

Dual-band filter passing SⅡ (672nm) and OIII (500.7nm) emission lines Designed for one-shot-color cameras to capture data often missed by Hα/OIII ...

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Askar Colour Magic Super D Ha/OIII & SII/OIII (D1+D2) Filter Package

Dual-Bandpass Filter Set (OIII 6.5nm, Hα/SII 8.5nm) Includes D1 (Hα+OIII) and D2 (SII+OIII) Filters Enables SHO-like imaging with color cameras Hi...

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Askar Colour Magic Super Ha/OIII D1 Filter - 2"

Dual-Bandpass: 8.5nm H-alpha & 6.5nm OIII Peak Transmittance: >85% at 500.7nm and 656.6nm Light Pollution Suppression: ≥OD5 blocking from 2...

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Askar Colour Magic Super SII/OIII D2 Filter - 2"

Dual-band filter passing OIII (6.5nm) and SII (8.5nm) wavelengths Peak transmittance of 85% for maximum signal capture Designed for color cameras ...

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IDAS GNB Galaxy & Nebula Booster Filter - transmission curve with IMX294 sensor QE
IDAS GNB Galaxy & Nebula Booster Filter - 2" (M48) mounted
CA$210.00 - CA$459.00
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IDAS GNB Galaxy & Nebula Booster Filter

Dual-bandpass design passes H-alpha, OIII, and Near-Infrared (NIR) wavelengths The world's first filter for imaging both nebulae and galaxies Avai...

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CA$210.00 - CA$459.00
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IDAS NB1 Nebula Booster Filter
CA$245.00 - CA$297.00
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IDAS NB1 Nebula Booster Filter

Dual-band filter for One-Shot-Color (OSC) cameras Passes H-Alpha, NII, H-Beta, and OIII emission lines ~20nm and ~32nm bandpasses Passband shifted...

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CA$245.00 - CA$297.00
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CA$245.00 - CA$297.00
CA$245.00
IDAS NBZ-II Dual-Band H-Alpha/OIII Nebula Booster Filter - transmission curve
IDAS NBZ-II Dual-Band H-Alpha/OIII Nebula Booster Filter - 2" (M48) mounted
CA$417.00 - CA$487.00
CA$417.00 - CA$487.00
CA$417.00 - CA$487.00
CA$417.00

IDAS NBZ-II Dual-Band H-Alpha/OIII Nebula Booster Filter

Dual-bandpass design passes H-alpha (9.5nm) and OIII (8nm) wavelengths Keeps 80% or more transmittance in fast systems around f/2, where some 7nm ...

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CA$417.00 - CA$487.00
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CA$251.00 - CA$363.00
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Optolong L-Enhance Filter

Dual-bandpass filter isolates H-Alpha, H-Beta, and OIII emission lines Peak transmission of over 90% for maximum signal Blocks over 99% of light p...

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Optolong L-Extreme + L-Synergy L2 Dual-Combo Filter Set - 2"

Includes L-eXtreme (H-alpha + OIII) and L-Synergy (SII + OIII) filters Enables Hubble Palette (SHO) imaging with one-shot color cameras Captures t...

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CA$335.00 - CA$432.00
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Optolong L-Extreme Filter

Narrow dual-bandpass filter for H-Alpha and OIII Blocks >99% of light pollution emission lines Peak transmission of >90% at critical wavelen...

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CA$335.00 - CA$432.00
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Optolong L-Para HA/OIII 10nm Filter - 2"

Dual Narrowband H-Alpha & OIII Filter Suppresses Mercury, Sodium & LED Light Pollution Optimized for Fast-Ratio Systems (RASA, HyperStar) ...

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Choosing Bandwidth

  • 3 nm: Maximum contrast and the smallest stars, best under heavy light pollution and bright Moon. Needs longer exposures. Optolong L-Ultimate, Antlia ALP-T 3 nm, SVBONY SV220 3 nm, Askar E1.
  • 5 to 7 nm: The best balance for most users, with good contrast and reasonable exposures. Optolong L-Extreme, Antlia ALP-T 5 nm, SVBONY SV220 7 nm.
  • 10 nm and wider, multi-band: Brighter and more forgiving, passes H-beta too in some designs. Gentler star colour. Optolong L-Enhance, L-Quad Enhance, L-Para.
  • SII/OIII filters: A second filter such as Optolong L-Synergy or Askar C2, D2 and E2 adds sulphur data for bicolour or Hubble-palette-style images with a colour camera.

Fast Optics and Filter Choice

In fast systems below about f/4, light enters the filter at steeper angles and the passband shifts toward blue. Very narrow filters can then cut into the emission line. For RASA, HyperStar and fast Newtonians, choose a filter rated for fast optics, often called Highspeed.

What We Check With You

  • Sky brightness and targets: Bortle 8 suburbs and bright emission nebulae call for 3 to 5 nm. Darker skies leave room for wider filters.
  • Focal ratio: We match the filter design to the speed of your telescope.
  • Size and mounting: 1.25-inch, 2-inch or a filter drawer, depending on your sensor and corrector.

Dual-Band Filters: Frequently Asked Questions

Do dual-band filters work on galaxies?

Not well. Galaxies emit across the whole spectrum, so a dual-band filter blocks most of their light. Use them for emission nebulae, and a broadband filter or dark skies for galaxies.

Can I use a dual-band filter with a mono camera?

Technically yes, but a mono camera cannot separate the two lines. Single-line narrowband filters are better for mono.

Why are my stars red or pink with a dual-band filter?

Stars are broadband, so only a little of their light passes. Processing tools that reduce or recolour stars help a lot.

Imaging nebulae from the city?

Tell us your camera, telescope focal ratio and sky. We will recommend the bandwidth that suits your setup.