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Filters

A filter decides what light reaches your sensor or your eye, and under Canadian suburban skies that decision often matters more than aperture. The right narrowband filter can make a nebula imageable from a driveway that visually shows almost nothing. David Astro carries filters in Canada — narrowband, LRGB, light pollution, planetary, solar and scientific — in 1.25", 2", 31 mm, 36 mm and unmounted formats, shipped from Canadian stock.

Filter selection is where our team spends a lot of time, because bandwidth, f-ratio and sensor size interact in ways that are not obvious from a product page. Tell us your telescope and camera and we will recommend a set that works together.

Filters

CA$199.00 - CA$377.00
CA$199.00 - CA$377.00
CA$199.00 - CA$377.00
CA$199.00

Optolong L-Pro Filter

Options available
13 variants in stock

Multi-Bandpass Light Pollution Suppression Effective Spectrum from 380-750nm Maintains Natural Color Balance on Broadband Targets High Transmissio...

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CA$199.00 - CA$377.00
CA$199.00 - CA$377.00
CA$199.00 - CA$377.00
CA$199.00
CA$558.00 - CA$558.00
CA$558.00
CA$558.00 - CA$558.00
CA$558.00

Optolong L-Quad Enhance + L-Para L1 Dual-Combo Filter Set - 2"

OPT-L1-SET
4 in stock

L-Quad Enhance Filter: A quad-bandpass filter designed for balanced RGB color from broadband targets. L-Para L1 Filter: A dual-narrowband filter...

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CA$558.00 - CA$558.00
CA$558.00
CA$558.00 - CA$558.00
CA$558.00
CA$278.00 - CA$278.00
CA$278.00
CA$278.00 - CA$278.00
CA$278.00

Optolong L-Quad Enhance Filter

OPT-14702
4 in stock

Quad-bandpass design for color cameras Suppresses light pollution with OD2-OD4 blocking depth Maintains sharpness with a λ/4 transmitted wavefront...

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CA$278.00 - CA$278.00
CA$278.00
CA$278.00 - CA$278.00
CA$278.00
CA$432.00 - CA$432.00
CA$432.00
CA$432.00 - CA$432.00
CA$432.00

Optolong L-Synergy 7nm SII/OIII Dual Narrowband Filter

OPT-LSYNERGY
3 in stock

Captures Sulfur-II and Oxygen-III Emission Lines Simultaneously Engineered for Hubble Palette (SHO) Imaging with Color Cameras Strict 7nm Bandpass...

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CA$432.00 - CA$432.00
CA$432.00
CA$432.00 - CA$432.00
CA$432.00
CA$404.00 - CA$545.00
CA$404.00 - CA$545.00
CA$404.00 - CA$545.00
CA$404.00

Optolong L-Ultimate Ha/OIII 3nm Filter

Options available
14 variants in stock

Dual 3nm bandpass isolates Hydrogen-alpha and Oxygen-III emission lines Blocks light pollution across the 300-1000nm spectrum Greater than OD4 blo...

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CA$404.00 - CA$545.00
CA$404.00 - CA$545.00
CA$404.00 - CA$545.00
CA$404.00
CA$517.00 - CA$797.00
CA$517.00 - CA$797.00
CA$517.00 - CA$797.00
CA$517.00

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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CA$517.00 - CA$797.00
CA$517.00 - CA$797.00
CA$517.00 - CA$797.00
CA$517.00
CA$349.00 - CA$503.00
CA$349.00 - CA$503.00
CA$349.00 - CA$503.00
CA$349.00

Optolong LRGB Filter Set

Options available
9 variants in stock

Complete 4-filter LRGB set for monochrome cameras High average transmission of over 90% for maximum signal Blocks sodium light pollution at 589nm ...

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CA$349.00 - CA$503.00
CA$349.00 - CA$503.00
CA$349.00 - CA$503.00
CA$349.00
CA$931.00 - CA$1,413.00
CA$931.00 - CA$1,413.00
CA$931.00 - CA$1,413.00
CA$931.00

Optolong LRGB, Ha, OIII & SII Filter Set

Options available
3 variants in stock

Complete 7-filter set for monochrome astrophotography Includes Luminance, Red, Green, and Blue broadband filters Includes 3nm Hydrogen-alpha, Oxyg...

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CA$931.00 - CA$1,413.00
CA$931.00 - CA$1,413.00
CA$931.00 - CA$1,413.00
CA$931.00
Optolong Moon & Skyglow Filter
CA$45.00 - CA$67.00
CA$45.00 - CA$67.00
CA$45.00 - CA$67.00
CA$45.00

Optolong Moon & Skyglow Filter

Options available

Blocks over 99% of common light pollution emission lines Maintains over 90% average transmission for bright, detailed views λ/4 transmitted wavefr...

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CA$45.00 - CA$67.00
CA$45.00 - CA$67.00
CA$45.00 - CA$67.00
CA$45.00
Optolong Night Sky H-Alpha IR Pass Filter
CA$111.00 - CA$167.00
CA$111.00 - CA$167.00
CA$111.00 - CA$167.00
CA$111.00

Optolong Night Sky H-Alpha IR Pass Filter

Options available

Passes Infrared Light >650nm Blocks Visible Light from 300-570nm Average Transmission >90% 1.85mm Thick Optical Glass Substrate λ/4 Transmit...

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CA$111.00 - CA$167.00
CA$111.00 - CA$167.00
CA$111.00 - CA$167.00
CA$111.00
Optolong OIII 18nm Nebula Filter
CA$111.00 - CA$151.00
CA$111.00 - CA$151.00
CA$111.00 - CA$151.00
CA$111.00

Optolong OIII 18nm Nebula Filter

Options available
2 variants in stock

18nm Bandpass Centered on OIII Emission Lines (500nm) Greater than 80% Average Light Transmission (Tave) Blocks >99% of Major Light Pollution L...

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CA$111.00 - CA$151.00
CA$111.00 - CA$151.00
CA$111.00 - CA$151.00
CA$111.00
Optolong OIII 3nm Narrowband Filter
CA$475.00 - CA$587.00
CA$475.00 - CA$587.00
CA$475.00 - CA$587.00
CA$475.00

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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CA$475.00 - CA$587.00
CA$475.00 - CA$587.00
CA$475.00 - CA$587.00
CA$475.00
Optolong OIII 6.5nm Narrowband Filter
CA$223.00 - CA$321.00
CA$223.00 - CA$321.00
CA$223.00 - CA$321.00
CA$223.00

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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CA$223.00 - CA$321.00
CA$223.00 - CA$321.00
CA$223.00 - CA$321.00
CA$223.00
Optolong SII 3nm Narrowband Filter
CA$475.00 - CA$587.00
CA$475.00 - CA$587.00
CA$475.00 - CA$587.00
CA$475.00

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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CA$475.00 - CA$587.00
CA$475.00 - CA$587.00
CA$475.00 - CA$587.00
CA$475.00
Optolong SII 6.5nm Narrowband Filter
CA$223.00 - CA$321.00
CA$223.00 - CA$321.00
CA$223.00 - CA$321.00
CA$223.00

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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CA$223.00 - CA$321.00
CA$223.00 - CA$321.00
CA$223.00 - CA$321.00
CA$223.00
CA$77.00 - CA$161.00
CA$77.00 - CA$161.00
CA$77.00 - CA$161.00
CA$77.00

Optolong UHC Filter

Options available
9 variants in stock

Reduces skyglow from artificial and natural light pollution Blocks >99% of mercury vapor and sodium vapor light Passes key nebula emission line...

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CA$77.00 - CA$161.00
CA$77.00 - CA$161.00
CA$77.00 - CA$161.00
CA$77.00
CA$62.00 - CA$91.00
CA$62.00 - CA$91.00
CA$62.00 - CA$91.00
CA$62.00

Optolong UV/IR Cut Filter

Options available
14 variants in stock

Blocks Ultraviolet (UV) and Infrared (IR) wavelengths Improves image sharpness and reduces star bloat Functions as a luminance (L) filter for mono...

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CA$62.00 - CA$91.00
CA$62.00 - CA$91.00
CA$62.00 - CA$91.00
CA$62.00
CA$52.00 - CA$64.00
CA$52.00 - CA$64.00
CA$52.00 - CA$64.00
CA$52.00

Optolong Variable Polarizing Filter

Options available
3 variants in stock

Continuously Variable Light Transmission Available in 1.25" and 2" Barrel Sizes Ideal for Lunar, Planetary, and Terrestrial Viewing Reduces Glare ...

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CA$52.00 - CA$64.00
CA$52.00 - CA$64.00
CA$52.00 - CA$64.00
CA$52.00
CA$470.00 - CA$470.00
CA$470.00
CA$470.00 - CA$470.00
CA$470.00

Pegasus Astro LRGB Filter Set - 2"

PEG-FLTR-2M-LRGB

Complete 4-filter LRGB set for broadband deep-sky imaging Standard 2-inch mounted format for wide compatibility Guaranteed 1/4 wavefront optical p...

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CA$470.00 - CA$470.00
CA$470.00
CA$470.00 - CA$470.00
CA$470.00
Player One Anti-Halo PRO Dual-Band 2″ Ha+OIII filter
CA$699.00 - CA$699.00
CA$699.00
CA$699.00 - CA$699.00
CA$699.00

Player One Anti-Halo PRO Dual-Band Ha/OIII Filter - 2"

POA-AHP-HO-2

Advanced Halo Suppression: Specifically engineered to eliminate halos around even the brightest stars. Dual-Band Ha+OIII Design: Captures hydrog...

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CA$699.00 - CA$699.00
CA$699.00
CA$699.00 - CA$699.00
CA$699.00
CA$181.00 - CA$181.00
CA$181.00
CA$181.00 - CA$181.00
CA$181.00

Player One CH4 8nm Filter E-series - 1.25"

POA-CH4-125E

Isolates the 8nm methane (CH4) absorption band Standard 1.25″ filter cell format Optimized for modern CMOS and CCD planetary cameras E-series feat...

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CA$181.00 - CA$181.00
CA$181.00
CA$181.00 - CA$181.00
CA$181.00
Player One Ha 7nm Narrowband Filter S-series – 2"
Player One Ha 7nm Narrowband Filter S-series – 1.25"
CA$181.00 - CA$349.00
CA$181.00 - CA$349.00
CA$181.00 - CA$349.00
CA$181.00

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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CA$181.00 - CA$349.00
CA$181.00 - CA$349.00
CA$181.00 - CA$349.00
CA$181.00
Player One IR685nm 1.25″ IR-Pass Filter S-series
CA$39.00 - CA$39.00
CA$39.00
CA$39.00 - CA$39.00
CA$39.00

Player One IR685nm IR-Pass Filter S-series - 1.25"

POA-IR685

Passes infrared light with wavelengths greater than 685nm Standard 1.25" filter format for broad compatibility Significantly improves image stabil...

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CA$39.00 - CA$39.00
CA$39.00
CA$39.00 - CA$39.00
CA$39.00
Player One IR850nm 1.25″ IR-Pass Filter S-series
CA$39.00 - CA$39.00
CA$39.00
CA$39.00 - CA$39.00
CA$39.00

Player One IR850nm IR-Pass Filter S-series - 1.25"

POA-IR850

Passes Infrared Light at 850nm Standard 1.25" Filter Size Blocks Visible and Ultraviolet Light High-Quality Optical Glass Substrate Multi-Layer An...

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CA$39.00 - CA$39.00
CA$39.00
CA$39.00 - CA$39.00
CA$39.00

Filter Types and When Each One Earns Its Place

Filters do not add signal. They remove unwanted light so that the signal you want has better contrast against the background. Choosing well means knowing which unwanted light you are fighting.

  • Narrowband filters: Ha, OIII and SII passbands, typically 3 to 12 nm. Narrower bands reject more light pollution and moonlight but demand accurate focus and longer exposures.
  • LRGB filter sets: Parfocal luminance, red, green and blue for colour imaging with monochrome sensors, with the luminance channel carrying most of the detail.
  • Light pollution filters: Broadband rejection of mercury and sodium emission lines. Effective against older street lighting and much less effective against broad-spectrum LED.
  • Planetary and colour filters: Wratten-standard colour filters that raise contrast on specific planetary features — a red or orange filter on Mars, blue on Jupiter's belts.
  • Solar filters: Full-aperture white-light filters for safe observation of sunspots and transits.
  • Neutral density and polarizing: Variable brightness reduction for lunar observing without altering colour balance.

Why Choose David Astro for Filters

A filter that performs beautifully at f/7 can produce a shifted passband and soft results at f/3. That is the kind of detail worth asking about before ordering.

  • F-ratio matched recommendations: Narrowband passbands shift blueward in fast optical systems, so we recommend filters specified for your focal ratio rather than the narrowest available.
  • Sensor size and vignetting: We size filters to your sensor diagonal and filter wheel placement, so an undersized filter does not clip your corners.
  • Spacing accounted for: Filter glass shifts focus by roughly a third of its thickness, and we include that in the back-focus calculation we provide.
  • Authorized dealer: Genuine filters with full manufacturer warranty and verified coatings, in Canadian inventory and shipped domestically.
  • Ships from Canada: No duties or brokerage charges for Canadian buyers.

Filters in Canada — Frequently Asked Questions

Do light pollution filters still work under LED streetlights?
Much less well than they did under sodium lighting. LED emits across a broad spectrum, so there is no narrow band to reject. Narrowband filters remain effective because they pass only emission lines regardless of what the streetlight does.
How narrow should my Ha filter be?
For f/5 and slower, 3 to 5 nm gives excellent contrast. Below about f/4, the incident light cone shifts the passband and a 6 to 7 nm filter, or one specified for fast optics, performs better.
What size filters do I need?
Match the sensor diagonal plus the distance from filter to sensor. A 36 mm filter typically covers APS-C in a standard wheel; full frame usually needs 50 mm square or unmounted 2 inch.
Are filters shipped from Canada?
Yes, in-stock filters are held in our Canadian warehouse and reach Canadian customers without customs handling.

Building a filter set?

Tell us your telescope, camera and sky conditions and we will recommend the right bandwidths and sizes. Canadian stock, fast domestic shipping.