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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

CA$362.00 - CA$696.00
CA$362.00 - CA$696.00
CA$362.00 - CA$696.00
CA$362.00

Antlia Filtre à bande étroite H-alpha Pro de 3nm

Options available
8 variants in stock

Longueur d'onde centrale H-alpha de 656,3 nm Petit FHWM de 3 nm Transmission de crête élevée > 88 % Halos minimisés sur les étoiles b...

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CA$362.00 - CA$696.00
CA$362.00 - CA$696.00
CA$362.00 - CA$696.00
CA$362.00
CA$375.00 - CA$721.00
CA$375.00 - CA$721.00
CA$375.00 - CA$721.00
CA$375.00

Antlia 3nm Narrowband H-alpha Pro Highspeed Filter - f/2.6 to f/3.6

Options available
1 variants in stock

Pre-shifted 656.3nm H-alpha Central Wavelength for High-Speed Systems Optimized 3nm FHWM for f/2.6–f/3.6 High >90% Peak Transmission Enhanced S...

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CA$375.00 - CA$721.00
CA$375.00 - CA$721.00
CA$375.00 - CA$721.00
CA$375.00
CA$362.00 - CA$696.00
CA$362.00 - CA$696.00
CA$362.00 - CA$696.00
CA$362.00

Antlia Filtre à bande étroite OIII Pro de 3nm

Options available
8 variants in stock

Le filtre à bande étroite Antlia OIII Pro optimise le FWHM (pleine largeur moitié maximum) à 3 nm passe-bande . Au fur et à mesure que la bande pa...

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CA$362.00 - CA$696.00
CA$362.00 - CA$696.00
CA$362.00 - CA$696.00
CA$362.00
CA$375.00 - CA$721.00
CA$375.00 - CA$721.00
CA$375.00 - CA$721.00
CA$375.00

Antlia 3nm Narrowband OIII Pro Highspeed Filter - f/2.6 to f/3.6

Options available
1 variants in stock

Pre-shifted 500.7nm OIII Central Wavelength for High-Speed Systems Optimized 3nm FHWM for f/2.6–f/3.6 High >90% Peak Transmission Enhan...

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CA$375.00 - CA$721.00
CA$375.00 - CA$721.00
CA$375.00 - CA$721.00
CA$375.00
CA$362.00 - CA$696.00
CA$362.00 - CA$696.00
CA$362.00 - CA$696.00
CA$362.00

Antlia Filtre à bande étroite SII Pro de 3nm

Options available
7 variants in stock

Le filtre à bande étroite Antlia SII Pro optimise le FWHM (pleine largeur moitié maximum) à une bande passante de 3 nm. Au fur et à mesure que la ...

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CA$362.00 - CA$696.00
CA$362.00 - CA$696.00
CA$362.00 - CA$696.00
CA$362.00
CA$375.00 - CA$721.00
CA$375.00 - CA$721.00
CA$375.00 - CA$721.00
CA$375.00

Antlia 3nm Narrowband SII Pro Highspeed Filter - f/2.6 to f/3.6

Options available
1 variants in stock

Pre-shifted 500.7nm OIII Central Wavelength for High-Speed Systems Optimized 3nm FHWM for f/2.6–f/3.6 High >90% Peak Transmission Enhan...

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CA$375.00 - CA$721.00
CA$375.00 - CA$721.00
CA$375.00 - CA$721.00
CA$375.00
CA$263.00 - CA$497.00
CA$263.00 - CA$497.00
CA$263.00 - CA$497.00
CA$263.00

Antlia Filtre à bande étroite H-alpha Edge de 4.5nm

Options available
8 variants in stock

Le filtre à bande étroite Antlia H-alpha EDGE optimise le FWHM (pleine largeur demi-maximum) à une bande passante de 4,5 nm. La suppression de la...

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CA$263.00 - CA$497.00
CA$263.00 - CA$497.00
CA$263.00 - CA$497.00
CA$263.00
CA$263.00 - CA$497.00
CA$263.00 - CA$497.00
CA$263.00 - CA$497.00
CA$263.00

Antlia Filtre à bande étroite OIII Edge de 4.5nm

Options available
8 variants in stock

Le filtre à bande étroite Antlia OIII EDGE optimise le FWHM (pleine largeur demi-maximum) à une bande passante de 4,5 nm. La suppression de la de...

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CA$263.00 - CA$497.00
CA$263.00 - CA$497.00
CA$263.00 - CA$497.00
CA$263.00
CA$263.00 - CA$497.00
CA$263.00 - CA$497.00
CA$263.00 - CA$497.00
CA$263.00

Antlia Filtre à bande étroite SII Edge de 4.5nm

Options available
7 variants in stock

Le filtre à bande étroite Antlia SII EDGE optimise le FWHM (pleine largeur demi-maximum) à une bande passante de 4,5 nm. La suppression de la den...

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CA$263.00 - CA$497.00
CA$263.00 - CA$497.00
CA$263.00 - CA$497.00
CA$263.00
CA$554.00 - CA$554.00
CA$554.00
CA$554.00 - CA$554.00
CA$554.00

Antlia ALP-T Dual Band Ha&OIII 3nm

ANT-ALP-T-3NM-HAOIII
5 en stock

Precise Narrowband Filtering for Exceptional Contrast Enhanced Transmission for Superior Signal-to-Noise Ratio ...

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CA$554.00 - CA$554.00
CA$554.00
CA$554.00 - CA$554.00
CA$554.00
CA$1,008.00 - CA$1,008.00
CA$1,008.00
CA$1,008.00 - CA$1,008.00
CA$1,008.00

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

ANT-ALP-T-3NM-KIT

Precise Narrowband Filtering for Exceptional Contrast Enhanced Transmission for Superior Signal-to-Noise Ratio ...

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CA$1,008.00 - CA$1,008.00
CA$1,008.00
CA$1,008.00 - CA$1,008.00
CA$1,008.00
CA$511.00 - CA$511.00
CA$511.00
CA$511.00 - CA$511.00
CA$511.00

Antlia ALP-T Dual Band SII&Hβ 3.5nm

ANT-ALP-T-3NM-SIIHB
2 en stock

Precise Narrowband Filtering for Exceptional Contrast Enhanced Transmission for Superior Signal-to-Noise Ratio Anti-Reflection Coating to Reduce H...

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CA$511.00 - CA$511.00
CA$511.00
CA$511.00 - CA$511.00
CA$511.00
CA$980.00 - CA$980.00
CA$980.00
CA$980.00 - CA$980.00
CA$980.00

Antlia Kit de filtres duoband ALP-T 5nm Ha/OIII et SII/Hb - 2"

ANT-ALP-T-SET

CA$980.00 - CA$980.00
CA$980.00
CA$980.00 - CA$980.00
CA$980.00
CA$540.00 - CA$540.00
CA$540.00
CA$540.00 - CA$540.00
CA$540.00

Antlia Filtre duoband ALP-T Ha/OIII de 5nm

ANT-ALP-T-2

L' Antlia ALP-T double bande 5 nm Le filtre Ha&OIII est un filtre passe-ligne double conçu pour être utilisé principalement avec les appareil...

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CA$540.00 - CA$540.00
CA$540.00
CA$540.00 - CA$540.00
CA$540.00
CA$540.00 - CA$540.00
CA$540.00
CA$540.00 - CA$540.00
CA$540.00

Antlia Filtre duoband ALP-T haute vitesse Ha/OIII de 5nm

ANT-ALP-T-HS-2

Les filtres haute vitesse ALP-T double bande 5 nm sont encore optimisés pour fonctionner avec des systèmes d'imagerie à haute vitesse en décalant...

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CA$540.00 - CA$540.00
CA$540.00
CA$540.00 - CA$540.00
CA$540.00
CA$497.00 - CA$497.00
CA$497.00
CA$497.00 - CA$497.00
CA$497.00

Antlia Filtre duoband ALP-T SII/Hb de 5nm

ANT-ALP-T-SII-HB-2

Le filtre SII&Hb double bande 5 nm ALP-T est un filtre passe-ligne double, qui laisse passer la ligne rouge foncé Sulphur-II et la ligne bleu...

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CA$497.00 - CA$497.00
CA$497.00
CA$497.00 - CA$497.00
CA$497.00
CA$254.00 - CA$254.00
CA$254.00
CA$254.00 - CA$254.00
CA$254.00

Antlia Filtre Triband RGB Ultra

ANT-TRIBAND-V2
4 en stock

Il est conçu pour la suppression de la pollution lumineuse pour les caméras OSC et Mono. La conception spectrale a sélectionné les informations le...

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CA$254.00 - CA$254.00
CA$254.00
CA$254.00 - CA$254.00
CA$254.00
CA$1,678.00 - CA$1,678.00
CA$1,678.00
CA$1,678.00 - CA$1,678.00
CA$1,678.00

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

ASK-CM-E1E2
1 en stock

Enables SHO "Hubble Palette" imaging with a one-shot-color (OSC) camera Includes two 3nm dual-bandpass filters: E1 (Hα+OIII) and E2 (SII+OIII) Iso...

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CA$1,678.00 - CA$1,678.00
CA$1,678.00
CA$1,678.00 - CA$1,678.00
CA$1,678.00
CA$847.00 - CA$847.00
CA$847.00
CA$847.00 - CA$847.00
CA$847.00

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

ASK-ASKAR2DBE1
1 en stock

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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CA$847.00 - CA$847.00
CA$847.00
CA$847.00 - CA$847.00
CA$847.00
CA$847.00 - CA$847.00
CA$847.00
CA$847.00 - CA$847.00
CA$847.00

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

ASK-ASKAR2DBE2
1 en stock

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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CA$847.00 - CA$847.00
CA$847.00
CA$847.00 - CA$847.00
CA$847.00
CA$875.00 - CA$875.00
CA$875.00
CA$875.00 - CA$875.00
CA$875.00

Ensemble de filtres Askar 6 nm Colour Magic Ha/OIII et SII/OIII (D1+D2)

ASK-CM-D1D2
3 en stock

Ensemble double filtre : 6 nm Ha/OIII (D1) et 6 nm SII/OIII (D2) Optimisé pour l'astrophotographie à contraste élevé et à bande étroite ...

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CA$875.00 - CA$875.00
CA$875.00
CA$875.00 - CA$875.00
CA$875.00
CA$447.00 - CA$447.00
CA$447.00
CA$447.00 - CA$447.00
CA$447.00

Filtre Askar Color Magic Super Ha/OIII D1 6 nm - 2"

ASK-ASK2DNHOD1
4 en stock

Filtre à double bande étroite de 6 nm de largeur de bande pour les longueurs d'onde Ha et OIII Taille de 2 pouces pour une compatibilité avec d...

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CA$447.00 - CA$447.00
CA$447.00
CA$447.00 - CA$447.00
CA$447.00
CA$447.00 - CA$447.00
CA$447.00
CA$447.00 - CA$447.00
CA$447.00

Filtre Askar Color Magic Super SII/OIII D2 6 nm - 2"

ASK-ASK2DNSOD2
3 en stock

Filtre à double bande étroite de 6 nm pour les longueurs d'onde SII et OIII Taille de 2 pouces pour la compatibilité avec diverses config...

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CA$447.00 - CA$447.00
CA$447.00
CA$447.00 - CA$447.00
CA$447.00
CA$315.00 - CA$315.00
CA$315.00
CA$315.00 - CA$315.00
CA$315.00

Ensemble de filtres Askar Colour Magic Ha/OIII et SII/OIII (C1+C2)

ASK-CM-C1C2
2 en stock

Pack double filtre pour l'astrophotographie : Ha/OIII (C1) et SII/OIII (C2) Optimisé pour capturer de superbes images de nébuleuse avec u...

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CA$315.00 - CA$315.00
CA$315.00
CA$315.00 - CA$315.00
CA$315.00

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.