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Filtres à bande étroite

Narrowband imaging is what makes deep-sky astrophotography possible from a Canadian city. By passing only a few nanometres around a specific emission line, these filters reject almost all artificial light and most moonlight, so a nebula that is invisible visually from a suburban driveway becomes a viable multi-hour imaging target. David Astro stocks narrowband filters in Canada, held in Canadian inventory.

Bandwidth choice interacts with your telescope's focal ratio in ways that catch people out. Tell us your optic and camera and we will recommend a bandwidth that will actually perform in your system.

Filtres

$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00

Chroma Filtre SII Optimisé pour f/3 - 3nm

Options available

Les filtres SII isolent l'émission spectrale d'atomes de soufre ionisés individuellement, également courants dans les nébuleuses. L'émission se fa...

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$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00
Explore Scientific Nebula Filter H-Alpha 1.25-inch 12nm
$159.99 - $159.99
$159.99
$159.99 - $159.99
$159.99

Explore Scientific Nebula Filter H-Alpha 1.25-inch 12nm

ES-310135

Targets Hydrogen-Alpha emission nebulae 12nm bandpass for astrophotography 1.25-inch standard filter size Drastically improves contrast under ligh...

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$159.99 - $159.99
$159.99
$159.99 - $159.99
$159.99
Explore Scientific Nebula Filter H-Alpha 2-inch 12nm
$249.99 - $249.99
$249.99
$249.99 - $249.99
$249.99

Explore Scientific Nebula Filter H-Alpha 2-inch 12nm

ES-310130

Isolates the Hydrogen-alpha emission line at a 12nm bandpass Standard 2-inch filter format for modern focusers and filter wheels Dramatically incr...

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$249.99 - $249.99
$249.99
$249.99 - $249.99
$249.99
Explore Scientific Nebula Filter H-Alpha 2-inch 7nm
$299.99 - $299.99
$299.99
$299.99 - $299.99
$299.99

Explore Scientific Nebula Filter H-Alpha 2-inch 7nm

ES-310140

7nm H-Alpha Bandpass 2-inch Filter Format Isolates Hydrogen Emission Nebulae Blocks Urban Light Pollution Includes Individual Test Report Descr...

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$299.99 - $299.99
$299.99
$299.99 - $299.99
$299.99
Explore Scientific Nebula Filter S-II 1.25-inch 12nm
$159.99 - $159.99
$159.99
$159.99 - $159.99
$159.99

Explore Scientific Nebula Filter S-II 1.25-inch 12nm

ES-310115

Isolates the ionized sulfur (S-II) emission line at 672nm Features a 12nm bandpass to increase contrast Standard 1.25-inch filter format Ideal for...

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$159.99 - $159.99
$159.99
$159.99 - $159.99
$159.99
Explore Scientific Nebula Filter S-II 1.25-inch 6.5nm
$199.99 - $199.99
$199.99
$199.99 - $199.99
$199.99

Explore Scientific Nebula Filter S-II 1.25-inch 6.5nm

ES-310125

Isolates the ionized sulfur (S-II) emission line at 672nm Ultra-narrow 6.5nm bandpass for maximum contrast Standard 1.25-inch barrel size fits mos...

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$199.99 - $199.99
$199.99
$199.99 - $199.99
$199.99
Explore Scientific Nebula Filter S-II 2-inch 12nm
$249.99 - $249.99
$249.99
$249.99 - $249.99
$249.99

Explore Scientific Nebula Filter S-II 2-inch 12nm

ES-310110

Isolates the 672nm Sulfur-II (S-II) emission line 12nm bandpass for high-contrast views 2-inch filter size with standard threads Blocks light poll...

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$249.99 - $249.99
$249.99
$249.99 - $249.99
$249.99
Explore Scientific Nebula Filter S-II 2-inch 6.5nm
$299.99 - $299.99
$299.99
$299.99 - $299.99
$299.99

Explore Scientific Nebula Filter S-II 2-inch 6.5nm

ES-310120

6.5nm Narrow Bandpass Targets the 672nm Ionized Sulfur (S-II) Emission Line 2-inch Barrel Diameter for Larger Focusers Drastically Increases Contr...

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$299.99 - $299.99
$299.99
$299.99 - $299.99
$299.99
$339.00 - $419.00
$339.00 - $419.00
$339.00 - $419.00
$339.00

Optolong H-alpha 3nm Narrowband Filter

Options available
1 variants in stock

3nm Bandpass at 656nm Wavelength Maximizes Contrast for Emission Nebulae Extreme Rejection of Light Pollution and Skyglow Ion-Assisted, Anti-Refle...

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$339.00 - $419.00
$339.00 - $419.00
$339.00 - $419.00
$339.00
Optolong H-Alpha 7nm Narrowband Filter
$159.00 - $229.00
$159.00 - $229.00
$159.00 - $229.00
$159.00

Optolong H-Alpha 7nm Narrowband Filter

Options available
3 variants in stock

Isolates the 656nm Hydrogen-alpha emission line 7nm bandpass for maximum contrast Blocks mercury vapor, sodium vapor, and natural skyglow Ideal fo...

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$159.00 - $229.00
$159.00 - $229.00
$159.00 - $229.00
$159.00
Optolong Ha 7nm, OIII 6.5nm & SII 6.5nm Filter Set
$465.00 - $669.00
$465.00 - $669.00
$465.00 - $669.00
$465.00

Optolong Ha 7nm, OIII 6.5nm & SII 6.5nm Filter Set

Options available

H-alpha Filter: 7nm Bandpass centered at 656nm Oxygen-III Filter: 6.5nm Bandpass centered at 500nm Sulphur-II Filter: 6.5nm Bandpass Hubble Pa...

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$465.00 - $669.00
$465.00 - $669.00
$465.00 - $669.00
$465.00
Optolong Ha, OIII & SII 3nm Narrowband Filter Set
$960.00 - $1,199.00
$960.00 - $1,199.00
$960.00 - $1,199.00
$960.00

Optolong Ha, OIII & SII 3nm Narrowband Filter Set

Options available

Complete SHO set includes H-alpha, OIII, and SII filters Ultra-narrow 3nm bandpass for maximum contrast Isolates 656nm Ha and 500nm OIII emission ...

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$960.00 - $1,199.00
$960.00 - $1,199.00
$960.00 - $1,199.00
$960.00
$369.00 - $569.00
$369.00 - $569.00
$369.00 - $569.00
$369.00

Optolong LRGB + H-Alpha 7nm Filter Set

Options available

Complete 5-Filter LRGB and H-Alpha Set 7nm H-Alpha Filter Centered at 656.3nm Blocks 589nm Sodium Light Pollution Line High Transmission for Natur...

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$369.00 - $569.00
$369.00 - $569.00
$369.00 - $569.00
$369.00
$665.00 - $1,009.00
$665.00 - $1,009.00
$665.00 - $1,009.00
$665.00

Ensemble de filtres Optolong LRGB, Ha, OIII et SII

Options available
3 variants in stock

Le jeu de filtres Optolong LRGB est conçu pour un contraste maximal et avec des gradients extrêmement élevés pour une différenciation claire des co...

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$665.00 - $1,009.00
$665.00 - $1,009.00
$665.00 - $1,009.00
$665.00
Optolong OIII 3nm Narrowband Filter
$339.00 - $419.00
$339.00 - $419.00
$339.00 - $419.00
$339.00

Optolong OIII 3nm Narrowband Filter

Options available
1 variants in stock

3nm Spectral Bandpass 500nm Central Wavelength (OIII) Ion-Assisted Multi-Layer Coatings Optimized for Monochrome Cameras Available in 2" Mounted o...

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$339.00 - $419.00
$339.00 - $419.00
$339.00 - $419.00
$339.00
Optolong OIII 6.5nm Narrowband Filter
$159.00 - $229.00
$159.00 - $229.00
$159.00 - $229.00
$159.00

Optolong OIII 6.5nm Narrowband Filter

Options available
3 variants in stock

6.5nm Narrowband OIII Filter Centered on 500nm Wavelength Captures both 495.9nm and 500.7nm Emission Lines Blocks Light Pollution and Skyglow Idea...

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$159.00 - $229.00
$159.00 - $229.00
$159.00 - $229.00
$159.00
Optolong SII 3nm Narrowband Filter
$339.00 - $419.00
$339.00 - $419.00
$339.00 - $419.00
$339.00

Optolong SII 3nm Narrowband Filter

Options available
1 variants in stock

Isolates the Sulfur-II (SII) emission line for astrophotography Extremely narrow 3nm bandpass for maximum contrast Drastically reduces skyglow and...

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$339.00 - $419.00
$339.00 - $419.00
$339.00 - $419.00
$339.00
Optolong SII 6.5nm Narrowband Filter
$159.00 - $229.00
$159.00 - $229.00
$159.00 - $229.00
$159.00

Optolong SII 6.5nm Narrowband Filter

Options available
3 variants in stock

Isolates the Sulfur-II (SII) emission line at 672nm Tight 6.5nm bandpass for maximum contrast Enables imaging in heavily light-polluted skies and ...

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$159.00 - $229.00
$159.00 - $229.00
$159.00 - $229.00
$159.00
Player One Ha 7nm Narrowband Filter S-series – 2"
Player One Ha 7nm Narrowband Filter S-series – 1.25"
$129.00 - $249.00
$129.00 - $249.00
$129.00 - $249.00
$129.00

Player One Ha 7nm Narrowband Filter S-series

Options available

7nm Hydrogen-alpha (Ha) Narrowband Filter Available in 1.25" Threaded Cell and 2" Round Mounted Formats Optimized for Monochrome CMOS/CCD Cameras ...

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$129.00 - $249.00
$129.00 - $249.00
$129.00 - $249.00
$129.00
Player One OIII 7nm Narrowband Filter S-series – 2"
Player One OIII 7nm Narrowband Filter S-series – 1.25"
$129.00 - $249.00
$129.00 - $249.00
$129.00 - $249.00
$129.00

Player One OIII 7nm Narrowband Filter S-series

Options available

Oxygen-III (OIII) 7nm Narrowband Filter Available in 1.25" and 2" Sizes for Narrowband Astrophotography High-Transmission, Multi-Layer Coatings Hi...

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$129.00 - $249.00
$129.00 - $249.00
$129.00 - $249.00
$129.00
Player One SII 7nm Narrowband Filter S-series – 2"
Player One SII 7nm Narrowband Filter S-series – 1.25"
$129.00 - $249.00
$129.00 - $249.00
$129.00 - $249.00
$129.00

Player One SII 7nm Narrowband Filter S-series

Options available

Sulfur-II (SII) Narrowband Filter 7nm Narrowband Passband Available in 1.25" and 2" Mounted Formats Optimized for High-Contrast Astrophotography A...

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$129.00 - $249.00
$129.00 - $249.00
$129.00 - $249.00
$129.00
SVBONY SV227 H-Alpha 5nm Narrowband Filter - 2"
SVBONY SV227 H-Alpha 5nm Narrowband Filter - 2"
$93.33 - $93.33
$93.33
$93.33 - $93.33
$93.33

SVBONY SV227 H-Alpha 5nm Narrowband Filter - 2"

SV-W9187DB

Isolates the 656.3nm H-Alpha wavelength Aggressive 5nm Full Width at Half Maximum (FWHM) bandpass Peak transmittance of ≥90% for high signal throu...

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$93.33 - $93.33
$93.33
$93.33 - $93.33
$93.33
SVBONY SV227 OIII 5nm Narrowband Filter - 2"
SVBONY SV227 OIII 5nm Narrowband Filter - 2"
$93.33 - $93.33
$93.33
$93.33 - $93.33
$93.33

SVBONY SV227 OIII 5nm Narrowband Filter - 2"

SV-W9187DC

Isolates the Oxygen III emission line at 500.7nm Extremely narrow 5nm Full Width at Half Maximum (FWHM) bandpass Achieves ≥90% peak light transmit...

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$93.33 - $93.33
$93.33
$93.33 - $93.33
$93.33
SVBONY SV227 SHO 5nm H-Alpha OIII SII Narrowband Filter Set - 1.25"
SVBONY SV227 SHO 5nm H-Alpha OIII SII Narrowband Filter Set - 1.25"
$167.99 - $167.99
$167.99
$167.99 - $167.99
$167.99

SVBONY SV227 SHO 5nm H-Alpha OIII SII Narrowband Filter Set - 1.25"

SV-W9187A

Complete 1.25-inch SHO (SII, H-Alpha, OIII) filter set Tight 5nm bandpass for high-contrast imaging Peak transmission rate of ≥90% at key waveleng...

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$167.99 - $167.99
$167.99
$167.99 - $167.99
$167.99

Emission Lines, Bandwidth and Focal Ratio

Narrowband filters isolate the specific wavelengths that ionized gas emits. Narrower is not always better, because the passband shifts in a fast light cone and the exposure requirement rises.

  • Hydrogen-alpha at 656.3 nm: The strongest and most widely used emission line, showing nebulosity in extraordinary detail and working well even under a bright Moon.
  • Oxygen III at 500.7 nm: Reveals planetary nebulae, supernova remnants and the outer shells of emission nebulae; typically the weakest signal of the three and needs the most integration.
  • Sulphur II at 672.4 nm: The third channel of the Hubble palette, adding structural differentiation in bright nebulae.
  • 3 to 5 nm bandwidth: Maximum contrast under light pollution, best suited to f/5 and slower systems and to accurate, temperature-compensated focus.
  • 6 to 12 nm bandwidth: More forgiving of fast optics and shorter exposures, and a better match for one-shot colour cameras and systems faster than f/4.
  • Dual and multi-band filters: Pass two or more lines simultaneously for one-shot colour cameras, giving narrowband-like contrast without a filter wheel.

Why Choose David Astro for Narrowband Filters

A filter that is wrong for your focal ratio will underperform in a way that looks like a quality problem but is a specification problem.

  • Focal ratio matched: Below roughly f/4 the incident cone shifts a narrow passband off the emission line. We recommend bandwidths or fast-optic designs that account for this.
  • Sizing to sensor and wheel geometry: We calculate the filter size needed to avoid vignetting given your sensor diagonal and filter-to-sensor distance.
  • Focus offsets explained: Narrowband channels often need per-filter focus offsets, and we help set them up so you are not refocusing manually every filter change.
  • Authorized dealer: Genuine filters with verified coatings and full manufacturer warranty, in Canadian stock.
  • Domestic shipping: No duties or brokerage fees for Canadian orders.

Narrowband Filters in Canada — Frequently Asked Questions

Can I use narrowband with a colour camera?
Yes, most effectively with a dual-band filter that passes Ha and OIII together, since a colour sensor's Bayer array can separate them. Single-line filters work but waste three quarters of the pixels.
Is a 3 nm filter always better than 7 nm?
Not in fast systems. Below about f/4 the steep light cone shifts the passband and a 3 nm filter can lose signal. In an f/6 system under city skies, 3 nm gives noticeably better contrast.
Can I image through a full Moon?
With Ha, largely yes. Moonlight is broadband scattered sunlight, and a narrow Ha filter rejects nearly all of it. OIII suffers more because its wavelength sits closer to the peak of scattered light.
How long should narrowband exposures be?
Longer than broadband — typically 300 to 600 seconds per sub, depending on focal ratio and camera read noise. Total integration for a good narrowband image is usually measured in tens of hours.

Imaging from a light-polluted site?

Tell us your telescope, camera and focal ratio and we will recommend the right bandwidths. Ships from Canada.