Passer au contenu
Égalisation des prix Retours sous 30 jours* Parlez à un astronome avant d'acheter

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

Baader Planetarium Baader H-alpha 1.25" f/3 Ultra-Highspeed-Filter (3.5nm) – CMOS-optimized
$347.00 - $770.00
$347.00 - $770.00
$347.00 - $770.00
$347.00

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

Options available

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, an...

Afficher tous les détails
$347.00 - $770.00
$347.00 - $770.00
$347.00 - $770.00
$347.00
Baader Planetarium Baader H-alpha 1.25" Ultra-Narrowband-Filter (3.5nm) – CMOS-optimized
$352.00 - $795.00
$352.00 - $795.00
$352.00 - $795.00
$352.00

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

Options available

3.5nm Ultra-Narrow Bandpass Available in 1.25" & 2" mounted, 31mm, 36mm & 50.4mm round unmounted, and 50x50mm & 65x65mm square sizes C...

Afficher tous les détails
$352.00 - $795.00
$352.00 - $795.00
$352.00 - $795.00
$352.00
Baader Planetarium Baader H-Beta 1.25" Narrowband Filter (5.5nm) – CMOS-optimized
$244.00 - $559.00
$244.00 - $559.00
$244.00 - $559.00
$244.00

Baader Planetarium H-Beta Narrowband-Filter (5.5nm) – CMOS-optimized

Options available

Isolates Hydrogen-Beta (H-Beta) Emission Line 5.5nm FWHM Narrowband Passband Available in 1.25" & 2" Mounted, 31/36/50.4mm Round Unmounted and...

Afficher tous les détails
$244.00 - $559.00
$244.00 - $559.00
$244.00 - $559.00
$244.00
Baader Planetarium Baader O-III 1.25" f/2 Highspeed-Filter (6.5nm) – CMOS-optimized
$199.00 - $479.00
$199.00 - $479.00
$199.00 - $479.00
$199.00

Baader Planetarium O-III f/2 Highspeed-Filter (6.5nm) – CMOS-optimized

Options available

6.5nm FWHM Bandpass for O-III Optimized for f/3.4 and Faster High-Speed Optical Systems Available in 1.25" & 2" Mounted, 31mm, 36mm, 47.4mm (F...

Afficher tous les détails
$199.00 - $479.00
$199.00 - $479.00
$199.00 - $479.00
$199.00
Baader Planetarium Baader O-III 1.25" f/2 Ultra-Highspeed-Filter (4nm) – CMOS-optimized
$333.00 - $669.00
$333.00 - $669.00
$333.00 - $669.00
$333.00

Baader Planetarium O-III f/2 Ultra-Highspeed-Filter (4nm) – CMOS-optimized

Options available

4nm FWHM Bandpass Optimized for f/2 Ultra-Highspeed Systems Available in 1.25" & 2" Mounted, 31mm, 36mm, 47.4mm (FCCT) & 50.4mm Round Unmo...

Afficher tous les détails
$333.00 - $669.00
$333.00 - $669.00
$333.00 - $669.00
$333.00
Baader Planetarium Baader O-III 1.25" f/3 Ultra-Highspeed-Filter (4nm) – CMOS-optimized
$317.00 - $667.00
$317.00 - $667.00
$317.00 - $667.00
$317.00

Baader Planetarium O-III f/3 Ultra-Highspeed-Filter (4nm) – CMOS-optimized

Options available

4nm FWHM Ultra-Narrow Bandpass Optimized for f/3.4 to f/2.3 Optical Systems Available in 1.25" & 2" Mounted, 31mm, 36mm & 50.4mm Round Unm...

Afficher tous les détails
$317.00 - $667.00
$317.00 - $667.00
$317.00 - $667.00
$317.00
Baader Planetarium O-III 1.25" Super-G Filter (9nm) - CMOS optimiert
$108.00 - $200.00
$108.00 - $200.00
$108.00 - $200.00
$108.00

Baader Planetarium O-III Super-G Filter (9nm) – CMOS-optimized

Options available
2 variants in stock

9nm O-III Narrowband Passband Functions as a "Super-G" Green Filter Replacement CMOS-Optimized Coatings for High Contrast Reduces Impact of Atmosp...

Afficher tous les détails
$108.00 - $200.00
$108.00 - $200.00
$108.00 - $200.00
$108.00
Baader Planetarium Baader S-II 1.25" f/2 Highspeed-Filter (6.5nm) – CMOS-optimized
$195.00 - $475.00
$195.00 - $475.00
$195.00 - $475.00
$195.00

Baader Planetarium S-II f/2 Highspeed-Filter (6.5nm) – CMOS-optimized

Options available

6.5nm Sulfur-II Narrowband Filter Optimized for f/2 High-Speed Optical Systems Available in 1.25" & 2" Mounted, 31mm, 36mm, 50.4mm & 2" FC...

Afficher tous les détails
$195.00 - $475.00
$195.00 - $475.00
$195.00 - $475.00
$195.00
Baader Planetarium Baader S-II 1.25" f/2 Ultra-Highspeed-Filter (4nm) – CMOS-optimized
$324.00 - $671.00
$324.00 - $671.00
$324.00 - $671.00
$324.00

Baader Planetarium S-II f/2 Ultra-Highspeed-Filter (4nm) – CMOS-optimized

Options available

4nm FWHM Bandpass for Sulfur-II (S-II) Engineered for f/2 Ultra-Highspeed Optical Systems Available in 1.25" & 2" Mounted, 31mm, 36mm, 50.4mm ...

Afficher tous les détails
$324.00 - $671.00
$324.00 - $671.00
$324.00 - $671.00
$324.00
Baader Planetarium Baader S-II 1.25" f/3 Ultra-Highspeed-Filter (4nm) – CMOS-optimized
$324.00 - $660.00
$324.00 - $660.00
$324.00 - $660.00
$324.00

Baader Planetarium S-II f/3 Ultra-Highspeed-Filter (4nm) – CMOS-optimized

Options available

4nm Bandwidth (FWHM) Pre-Shifted for Fast f/3 Optical Systems Available in 1.25" & 2" Mounted, 31mm, 36mm & 50.4mm Unmounted Round, and 50...

Afficher tous les détails
$324.00 - $660.00
$324.00 - $660.00
$324.00 - $660.00
$324.00
Baader Planetarium Baader S-II 1.25" Ultra-Narrowband-Filter (4nm) – CMOS-optimized
$324.00 - $694.00
$324.00 - $694.00
$324.00 - $694.00
$324.00

Baader Planetarium S-II Ultra-Narrowband-Filter (4nm) – CMOS-optimized

Options available

4nm Full-Width Half-Maximum (FWHM) Bandpass Optimized for Modern CMOS Sensors Available in 1.25" (M28.5 x 0.6) & 2" Mounted, 31mm, 36mm & ...

Afficher tous les détails
$324.00 - $694.00
$324.00 - $694.00
$324.00 - $694.00
$324.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00

Chroma Filtre H-alpha - 3nm

Options available

Les filtres H-alpha sont essentiels pour l'imagerie des nébuleuses et autres objets riches en hydrogène ionisé. À 656,3 nm, un filtre d'émission à ...

Afficher tous les détails
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00

Chroma Filtre H-alpha - 5nm

Options available

Les filtres H-alpha sont essentiels pour l'imagerie des nébuleuses et autres objets riches en hydrogène ionisé. À 656,3 nm, un filtre d'émission à...

Afficher tous les détails
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00
$275.00 - $830.00
$275.00 - $830.00
$275.00 - $830.00
$275.00

Chroma Filtre H-alpha - 8nm

Options available

Les filtres H-alpha sont essentiels pour l'imagerie des nébuleuses et autres objets riches en hydrogène ionisé. À 656,3 nm, un filtre d'émission à...

Afficher tous les détails
$275.00 - $830.00
$275.00 - $830.00
$275.00 - $830.00
$275.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00

Chroma Filtre H-alpha Optimisé pour f/3 - 3nm

Options available

Les filtres H-alpha sont essentiels pour l'imagerie des nébuleuses et autres objets riches en hydrogène ionisé. À 656,3 nm, un filtre d'émission à...

Afficher tous les détails
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00

Chroma Filtre H-beta - 3nm

Options available

Les filtres H-bêta sont également utiles pour l'imagerie des nébuleuses et des objets riches en hydrogène ionisé. À 486,1 nm, un filtre à bande ét...

Afficher tous les détails
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00

Chroma Filtre H-beta - 5nm

Options available

Les filtres H-bêta sont également utiles pour l'imagerie des nébuleuses et des objets riches en hydrogène ionisé. À 486,1 nm, un filtre à bande ét...

Afficher tous les détails
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00

Chroma Filtre OIII - 3nm

Options available

Les filtres OIII de Chroma isolent la ligne d'émission primaire de 500,7 nm d'oxygène doublement ionisé. Après H-alpha, c'est la prochaine émissio...

Afficher tous les détails
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00

Chroma Filtre OIII - 5nm

Options available

Les filtres OIII de Chroma isolent la ligne d'émission primaire de 500,7 nm d'oxygène doublement ionisé. Après H-alpha, c'est la prochaine émissio...

Afficher tous les détails
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00
$275.00 - $830.00
$275.00 - $830.00
$275.00 - $830.00
$275.00

Chroma Filtre OIII - 8nm

Options available

Les filtres OIII de Chroma isolent la ligne d'émission primaire de 500,7 nm d'oxygène doublement ionisé. Après H-alpha, c'est la prochaine émissio...

Afficher tous les détails
$275.00 - $830.00
$275.00 - $830.00
$275.00 - $830.00
$275.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00

Chroma Filtre OIII Optimisé pour f/3 - 3nm

Options available

Les filtres OIII de Chroma isolent la ligne d'émission primaire de 500,7 nm d'oxygène doublement ionisé. Après H-alpha, c'est la prochaine émissio...

Afficher tous les détails
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00

Chroma Filtre SII - 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...

Afficher tous les détails
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00 - $1,550.00
$575.00
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00

Chroma Filtre SII - 5nm

Options available

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

Afficher tous les détails
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00 - $1,380.00
$460.00
$275.00 - $830.00
$275.00 - $830.00
$275.00 - $830.00
$275.00

Chroma Filtre SII - 8nm

Options available

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

Afficher tous les détails
$275.00 - $830.00
$275.00 - $830.00
$275.00 - $830.00
$275.00

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.