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Optical Accessories

Optical accessories are what turn one telescope into several. The same optical tube can be a wide-field imaging refractor, a high-power planetary instrument or a comfortable binocular-view visual scope depending on what you put behind it. David Astro carries a deep selection of eyepieces, diagonals, Barlows, reducers, flatteners, binoviewers and correctors in Canada, held in Canadian stock.

Our team uses this equipment on our own telescopes, so the advice you get is based on what actually works at a given focal ratio and under a given sky, not on a spec sheet. If you are deciding between two focal lengths or wondering whether a corrector will help your optic, ask us before you order.

Filters

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

Antlia 3nm Narrowband H-alpha Pro Filter

Options available
8 variants in stock

656.3nm H-alpha Central Wavelength Small 3nm FHWM High >88% Peak Transmission Minimized halos on bright stars Description Specificat...

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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 3nm Narrowband OIII Pro Filter

Options available
8 variants in stock

Antlia OIII Pro narrowband filter optimizes the FWHM (full width half maximum) to 3nmbandpass. As the bandwidth becomes narrower, the 3nm Pro narro...

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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 3nm Narrowband SII Pro Filter

Options available
7 variants in stock

Antlia SII Pro narrowband filter optimizes the FWHM (full width half maximum) to 3nm bandpass. As the bandwidth becomes narrower, the 3nm Pro narro...

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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 4.5nm Narrowband H-alpha Edge Filter

Options available
8 variants in stock

Antlia H-alpha EDGE narrowband filter optimizes the FWHM (full width half maximum) to 4.5nm bandpass. The suppression of optical density (OD)5 on ...

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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 4.5nm Narrowband OIII Edge Filter

Options available
8 variants in stock

Antlia OIII EDGE narrowband filter optimizes the FWHM (full width half maximum) to 4.5nm bandpass. The suppression of optical density (OD)5 on unw...

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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 4.5nm Narrowband SII Edge Filter

Options available
7 variants in stock

Antlia SII EDGE narrowband filter optimizes the FWHM (full width half maximum) to 4.5nm bandpass. The suppression of optical density (OD)5 on unwa...

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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 in 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 in 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 ALP-T Dualband 5nm Ha/OIII and SII/Hb Filter Set - 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 ALP-T Dualband 5nm Ha/OIII Filter

ANT-ALP-T-2

The Antlia ALP-T dual band 5nm Ha&OIII filter is a dual line-pass filter which was designed to be used primarily with one-shot color (OSC) cam...

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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 ALP-T Dualband 5nm Ha/OIII Highspeed Filter

ANT-ALP-T-HS-2

ALP-T Dual Band 5nm Highspeed Filters are further optimized to work with high-speed imaging systems by shifting slightly the passband and center w...

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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 ALP-T Dualband 5nm SII/Hb Filter

ANT-ALP-T-SII-HB-2

The ALP-T dual band 5nm SII&Hb filter is a dual line-pass filter, which lets the deep red Sulfur-II line and the blue Hydrogen-Beta line throu...

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CA$497.00 - CA$497.00
CA$497.00
CA$497.00 - CA$497.00
CA$497.00
CA$236.00 - CA$236.00
CA$236.00
CA$236.00 - CA$236.00
CA$236.00

Antlia CH4 Methane Filter - 1.25"

ANT-CH4
1 in stock

Antlia methane (CH4) filter is a specialized filter that allows light in the near infrared portion of the spectrum centered at 889nm to pass throug...

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CA$236.00 - CA$236.00
CA$236.00
CA$236.00 - CA$236.00
CA$236.00
CA$141.00 - CA$141.00
CA$141.00
CA$141.00 - CA$141.00
CA$141.00

Antlia H-beta and OIII Visual Filter - 1.25"

ANT-HB-OIII-1.25
3 in stock

Antlia HB-OIII filter is engineered specifically for night visual nebulae observation at a high contrast and Deep-sky astrophotography. Its transm...

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CA$141.00 - CA$141.00
CA$141.00
CA$141.00 - CA$141.00
CA$141.00
CA$55.00 - CA$55.00
CA$55.00
CA$55.00 - CA$55.00
CA$55.00

Antlia IR Pass 685nm Filter - 1.25"

ANT-IR685
3 in stock

The Antlia IR Pass 685nm filter is an absorptive filter that allows infrared light with wavelengths of more than 685nm to pass through. At these l...

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CA$55.00 - CA$55.00
CA$55.00
CA$55.00 - CA$55.00
CA$55.00
CA$55.00 - CA$55.00
CA$55.00
CA$55.00 - CA$55.00
CA$55.00

Antlia IR Pass 850nm Filter - 1.25"

ANT-IR850
3 in stock

The Antlia IR Pass 850nm filter is an absorptive filter that allows infrared light with wavelengths of more than 850nm to pass through. It is a su...

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CA$55.00 - CA$55.00
CA$55.00
CA$55.00 - CA$55.00
CA$55.00
CA$426.00 - CA$852.00
CA$426.00 - CA$852.00
CA$426.00 - CA$852.00
CA$426.00

Antlia LRGB-V Pro Filter Set

Options available
8 variants in stock

Four-Filter LRGB Complement Engineered for Monochrome CMOS/CCD Cameras Anti-Reflection Coated Optics Available in 5 Mounted and Unmounted Sizes ...

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CA$426.00 - CA$852.00
CA$426.00 - CA$852.00
CA$426.00 - CA$852.00
CA$426.00
CA$281.00 - CA$281.00
CA$281.00
CA$281.00 - CA$281.00
CA$281.00

Antlia Quad Band Light Pollution Filter - 2"

ANT-QUAD-2
5 in stock

The Antlia Quad Band Anti-Light Pollution Filter is a light suppression filter for color and monochrome cameras. It is able to shoot most deep sky...

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CA$281.00 - CA$281.00
CA$281.00
CA$281.00 - CA$281.00
CA$281.00
CA$254.00 - CA$254.00
CA$254.00
CA$254.00 - CA$254.00
CA$254.00

Antlia Triband RGB Ultra Filter V2

ANT-TRIBAND-V2
4 in stock

Enhanced Transmission for Superior Signal-to-Noise Ratio Anti-Reflection Coating to Reduce Halo Effect Optimized for Fast Optics up to f/2 Desc...

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CA$254.00 - CA$254.00
CA$254.00
CA$254.00 - CA$254.00
CA$254.00
CA$283.00 - CA$283.00
CA$283.00
CA$283.00 - CA$283.00
CA$283.00

Antlia U-Venus Filter - 1.25"

ANT-UVENUS
2 in stock

Antlia Venus-U filter is designed for imaging the cloud structure of Venus and Jupiter with CCD cameras on a telescope. Cloud details primarily re...

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CA$283.00 - CA$283.00
CA$283.00
CA$283.00 - CA$283.00
CA$283.00

Choosing Optical Accessories That Match Your Telescope

Every accessory in this collection modifies the light cone before it reaches your eye or sensor. The right choice depends almost entirely on your telescope's focal ratio, focal length and back-focus budget.

  • Eyepieces: Focal length sets magnification against your telescope's focal length; apparent field and eye relief determine how comfortable that magnification is to use.
  • Diagonals: Dielectric mirrors typically exceed 99% reflectivity; prisms can outperform them at f/10 and slower on planetary targets but introduce chromatic effects in fast refractors.
  • Barlow lenses and extenders: Multiply focal length for planetary work and push the focal plane outward, which is often the cheapest fix for a scope that will not reach focus with a diagonal.
  • Field flatteners and reducers: Correct field curvature and coma across large sensors; each has a fixed back-focus that must be hit precisely.
  • Binoviewers: Two-eye viewing that dramatically improves perceived detail on the Moon and planets, at the cost of significant added optical path.
  • Finders and reflex sights: Acquisition optics — the accessory most often skipped and most often missed.

Why Choose David Astro for Optical Accessories

Optics are easy to buy badly. A well-reviewed eyepiece can still be the wrong eyepiece for your focal ratio, exit pupil or sky.

  • Focal length guidance: We help you build a spaced eyepiece set rather than three focal lengths that overlap, and we calculate exit pupil against your aperture and typical seeing.
  • Corrector matching: We confirm that a flattener or reducer is designed for your telescope's focal ratio before you buy, since a mismatched corrector degrades a field rather than fixing it.
  • Authorized dealer: Full manufacturer warranty and verified authenticity on everything we list.
  • Canadian stock: In-stock optics ship from Canada, with no surprise duties or brokerage fees for Canadian customers.
  • Service and support after the sale: In-house diagnostics if something is not performing as expected.

Optical Accessories in Canada — Frequently Asked Questions

Will a premium eyepiece improve a modest telescope?
Usually yes at the edges of the field, especially in fast telescopes below f/6 where simpler designs struggle. On the axis at f/10, the difference between a good eyepiece and a premium one is much smaller.
How do I know if I need a flattener or a reducer?
A flattener corrects curvature at the same focal length. A reducer also shortens focal length, widening the field and speeding the system. If your stars are elongated only in the corners, you need a flattener; if you also want more field, a reducer.
Do binoviewers work in every telescope?
They add roughly 100 mm or more of optical path, so most refractors need a corrector or a Barlow-style element to reach focus. Schmidt-Cassegrains generally accommodate them without modification.
Is everything shipped domestically?
Yes. Anything shown as in stock is held in Canada and ships without customs delays for Canadian orders.

Match the accessory to the optic

Tell us your telescope and what you want to see, and we will recommend the right combination. Ships from Canada.