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IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.

Visual 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

$347.00 - $347.00
$347.00
$347.00 - $347.00
$347.00

Baader Mirror Diagonal - 2" ClickLock

BAA-2956100

2-inch Barrel Format Baader ClickLock Eyepiece Clamp High-Reflectivity Mirror Design Precision Machined Body Self-Centering Clamp Mechanism Des...

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$347.00 - $347.00
$347.00
$347.00 - $347.00
$347.00
$584.00 - $584.00
$584.00
$584.00 - $584.00
$584.00

Baader Mirror Diagonal w/ BBHS Coating - 2" ClickLock

BAA-2456115
Only 1 left!

2" BBHS star diagonal with 2" ClickLock terminal and black case. Provides greatest reflectance over most spectral range from 390 to 2000nm New inc...

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$584.00 - $584.00
$584.00
$584.00 - $584.00
$584.00
$335.00 - $335.00
$335.00
$335.00 - $335.00
$335.00

Baader Mirror Diagonal w/ BBHS Coating - T-2

BAA-2456103
1 in stock

BBHS® BroadBand Hard Silver Coating Protective Dielectric Overcoat Baader T-2 System Component Modular Threaded Connections Optimized for High Ref...

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$335.00 - $335.00
$335.00
$335.00 - $335.00
$335.00
Baader Planetarium Baader 1.25" Extension Tube for Long Focal Length Eyepieces
$42.00 - $42.00
$42.00
$42.00 - $42.00
$42.00

Baader Planetarium 1.25" Extension Tube for Long Focal Length Eyepieces

BAA-2456325

Enables Use of 30-42mm Eyepieces in Baader Maxbright Binoviewers Solves Image Merging Failures with Long Focal Length Designs Extends Eyepiece Bar...

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$42.00 - $42.00
$42.00
$42.00 - $42.00
$42.00
Baader Planetarium 2" BBHS® Mirror – Adjustable Star Diagonal
$579.00 - $579.00
$579.00
$579.00 - $579.00
$579.00

Baader Planetarium 2" BBHS® Mirror – Adjustable Star Diagonal

BAA-2456105
1 in stock

BBHS® Broad Band Hard Silver coating for maximum spectral range and color fidelity User-collimatable mirror in a CNC-machined aluminum housing The...

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$579.00 - $579.00
$579.00
$579.00 - $579.00
$579.00
Baader Planetarium FFC All-in-One T-2 Set – 3–4x magnification for 1.25" and T-2 cameras
$1,180.00 - $1,180.00
$1,180.00
$1,180.00 - $1,180.00
$1,180.00

Baader Planetarium FFC All-in-One T-2 Set – 3–4x magnification for 1.25" and T-2 cameras

BAA-2458281

Variable Magnification: 3x to 8x+ Optical Design: 4-Element with 2x CaF2 Fluorite Lenses Image Circle: 90mm Flat Field at 4x Magnification Set Mag...

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$1,180.00 - $1,180.00
$1,180.00
$1,180.00 - $1,180.00
$1,180.00
Baader Planetarium Glasspathcorrector 2" / 1.7x for Newtons
$291.00 - $291.00
$291.00
$291.00 - $291.00
$291.00

Baader Planetarium Glasspathcorrector 2" / 1.7x for Newtons

BAA-2456300

1.7x focal length multiplier Enables binoviewer use in Newtonian telescopes Integrated coma corrector for sharp edge-of-field stars Designed for 2...

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$291.00 - $291.00
$291.00
$291.00 - $291.00
$291.00
Baader Planetarium Glasspathcorrector 1.25x for Baader-Binoviewer with Zeiss ring dovetail (MaxBright® II and Mark V)
$144.00 - $149.00
$144.00 - $149.00
$144.00 - $149.00
$144.00

Baader Planetarium Glasspathcorrector for Baader-Binoviewer with Zeiss ring dovetail (MaxBright® II and Mark V)

Options available

Available in 1.25x and 1.7x magnification factors Corrects prism-induced color aberrations in fast telescopes Extends optical path to solve backfo...

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$144.00 - $149.00
$144.00 - $149.00
$144.00 - $149.00
$144.00
Baader Planetarium M68 ClickLock® Mirror Diagonal
$358.00 - $358.00
$358.00
$358.00 - $358.00
$358.00

Baader Planetarium M68 ClickLock® Mirror Diagonal

BAA-2956100Z

2-inch ClickLock Eyepiece Clamp M68 (Zeiss) Threaded Telescope Connection All-Metal Mirror Diagonal Housing Replaces Standard Slip-Fit Diagonals E...

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$358.00 - $358.00
$358.00
$358.00 - $358.00
$358.00
$279.00 - $279.00
$279.00
$279.00 - $279.00
$279.00

Baader Star Diagonal Prism w/ Zeiss Spec Prism & BBHS Coating - T-2

BAA-2456095
1 in stock

Zeiss-Specification Right-Angle Prism Baader BBHS® (Broadband Hard Silver) Coatings T-2 (M42x0.75) Threads on Input and Output Faces Solid, All-Me...

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$279.00 - $279.00
$279.00
$279.00 - $279.00
$279.00
$56.00 - $56.00
$56.00
$56.00 - $56.00
$56.00

Baader T-2 Locking Ring w/ Lever for MaxBright II

BAA-2458271

Creates a rigid, direct-thread connection for binoviewers Enables precise rotational adjustment and locking Features a repositionable lever for er...

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$56.00 - $56.00
$56.00
$56.00 - $56.00
$56.00
$469.00 - $469.00
$469.00
$469.00 - $469.00
$469.00

Baader Telecentric System TZ-2 - 2x

BAA-2459255

Telecentric with 2" outer diameter and T-2 threads on both sides Aplanatic, with 2x focal length extension to achieve a parallel f/30 beam in conj...

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$469.00 - $469.00
$469.00
$469.00 - $469.00
$469.00
$652.00 - $652.00
$652.00
$652.00 - $652.00
$652.00

Baader Telecentric System TZ-3 - 3x Research Grade

BAA-2459257

3x Telecentric Focal Extender Engineered for Narrowband H-alpha Solar Filters Produces a Parallel (Collimated) Light Path Maintains Etalon Bandpas...

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$652.00 - $652.00
$652.00
$652.00 - $652.00
$652.00
$469.00 - $469.00
$469.00
$469.00 - $469.00
$469.00

Baader Telecentric System TZ-4 - 4x

BAA-2459256

4x Telecentric Focal Extender Engineered for Narrowband H-alpha Solar Filters Creates a Parallel f/30 Light Path Optimized Coatings for 656nm Wave...

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$469.00 - $469.00
$469.00
$469.00 - $469.00
$469.00
$69.95 - $69.95
$69.95
$69.95 - $69.95
$69.95

Celestron 1.25" Universal Barlow and T-Adapter

CEL-93640

Three-in-one design: 2x visual Barlow, prime focus T-adapter, and tele-extended T-adapter Doubles the magnification of any 1.25" eyepiece Connects...

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$69.95 - $69.95
$69.95
$69.95 - $69.95
$69.95
$45.00 - $45.00
$45.00
$45.00 - $45.00
$45.00

Celestron 45-Degree Erect Image Diagonal

CEL-94112-A

Corrects image orientation for terrestrial viewing Produces right-side-up and left-to-right correct images Comfortable 45-degree viewing ang...

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$45.00 - $45.00
$45.00
$45.00 - $45.00
$45.00
$20.95 - $20.95
$20.95
$20.95 - $20.95
$20.95

Celestron Basic Smartphone Adapter, 1.25”

CEL-81035

Connects smartphones to eyepieces with a 29mm - 45mm outer diameter Securely holds phones from 56mm to 97mm wide Enables afocal photography (digis...

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$20.95 - $20.95
$20.95
$20.95 - $20.95
$20.95
$159.95 - $159.95
$159.95
$159.95 - $159.95
$159.95

Celestron Dielectric Star Diagonal with Twist-Lock - 1.25"

CEL-93571

Over 99% reflectivity from 58-layer dielectric mirror coatings 1.25” Twist-Lock holder provides a secure, self-centering grip Diffraction-limited ...

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$159.95 - $159.95
$159.95
$159.95 - $159.95
$159.95
$259.95 - $259.95
$259.95
$259.95 - $259.95
$259.95

Celestron Dielectric Star Diagonal with Twist-Lock - 2"

CEL-93573

Delivers over 99% reflectivity with 58 layers of dielectric coatings Secure, self-centering Twist-Lock mechanism for 2" and 1.25" eyepieces Includ...

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$259.95 - $259.95
$259.95
$259.95 - $259.95
$259.95
$159.95 - $159.95
$159.95
$159.95 - $159.95
$159.95

Celestron Luminos 2.5x Barlow - 2"

CEL-93436

Instantly increases eyepiece magnification by 2.5x 4-element apochromatic optics deliver high-contrast, color-correct views Accepts both 2" and 1....

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$159.95 - $159.95
$159.95
$159.95 - $159.95
$159.95
$184.95 - $184.95
$184.95
$184.95 - $184.95
$184.95

Celestron Mirror Diagonal with XLT Coatings - 2"

CEL-93527

Interferometer-tested mirror with 1/10 wave or better surface accuracy Features Celestron's proprietary XLT optical coatings for maximum light tra...

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$184.95 - $184.95
$184.95
$184.95 - $184.95
$184.95
$41.95 - $41.95
$41.95
$41.95 - $41.95
$41.95

Celestron NexGO Universal Smartphone Adapter

CEL-81036
4 in stock

Fits any eyepiece from 25.4mm to 44.45mm in diameter Accommodates smartphones from 58mm to 103mm wide Precise X-Y rack and pinion adjustment for f...

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$41.95 - $41.95
$41.95
$41.95 - $41.95
$41.95
$66.95 - $66.95
$66.95
$66.95 - $66.95
$66.95

Celestron NexYZ 3-Axis Universal Smartphone Adapter

CEL-81055

Patented 3-axis rack and pinion smartphone alignment Fits eyepieces from 35mm to 60mm in diameter Includes adapters to fit microscope eyepieces do...

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$66.95 - $66.95
$66.95
$66.95 - $66.95
$66.95
$41.95 - $41.95
$41.95
$41.95 - $41.95
$41.95

Celestron Omni 2x Barlow - 1.25"

CEL-93326
1 in stock

Instantly doubles the magnification of any 1.25" eyepiece 2-element, fully multi-coated optics for sharp, high-contrast views Maintains the origin...

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$41.95 - $41.95
$41.95
$41.95 - $41.95
$41.95

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.