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Sales & Clearance

Astronomy sales at David Astro — current markdowns across the catalogue, including open-box units, discontinued models still fully supported, and overstock we would rather see on a telescope than on a shelf. Everything here is held in Canadian stock and carries the same warranty and support as full-price inventory.

Reduced price does not mean reduced service. We will still calculate your back-focus, confirm compatibility and support the item after the sale, exactly as we would for anything else in the catalogue.

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$55.00 USD
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$52.25 USD
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William Optics 48mm T-Mount for Fuji FX - Black

Connects M48-threaded correctors to Fujifilm X-mount (Fuji FX) mirrorless cameras Wide 48mm aperture minimizes vignetting on APS-C sensors Precise...

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$55.00 USD
$52.25 USD
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$39.00 USD
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$39.00 USD
$37.05 USD
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$37.05 USD

William Optics 48mm T-Mount for Nikon F

Connects M48 Accessories to Nikon F-Mount Cameras Precisely machined 8.2 mm optical length achieves exact 55mm back focus when combined with camer...

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$39.00 USD
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$39.00 USD
$37.05 USD
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$37.05 USD
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$68.00 USD
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$68.00 USD
$64.60 USD
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$64.60 USD

William Optics 48mm T-Mount for Nikon Z

Connects M48 accessories to Nikon Z-mount mirrorless cameras Precisely machined 38.4 mm optical length achieves about 55mm back focus when combine...

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$68.00 USD
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$68.00 USD
$64.60 USD
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$64.60 USD
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$39.00 USD
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$37.05 USD
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$37.05 USD

William Optics 48mm T-Mount for Pentax K - Black

Connects Pentax K-Mount Cameras to M48 Accessories Precisely machined 9.3 mm optical length achieves exact 55mm back focus when combined with came...

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$39.00 USD
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$37.05 USD
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$37.05 USD
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$55.00 USD
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$52.25 USD
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William Optics 48mm T-Mount for Sony E - Black

Connects Sony E-mount cameras to M48 accessories Provides a precise 36.7 mm optical length M48 (female) threads reduce vignetting on large sensors...

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$52.25 USD
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$148.00 USD - $178.00 USD
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William Optics 50mm Guiding Scope

50mm Aperture Doublet Lens 200mm Focal Length f/4.0 Focal Ratio 1.25" RotoLock Eyepiece Holder Total Weight: 0.42 kg / 0.93 lbs Description FAQ...

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$148.00 USD - $178.00 USD
$148.00 USD
$140.60 USD - $169.10 USD
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$140.60 USD
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William Optics 54mm Flattener Extender for GT81 WIFD
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$68.00 USD
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$68.00 USD
$64.60 USD
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William Optics 54mm Flattener Extender for GT81 WIFD

Provides a precise 54mm of optical length Connects the FLAT68III flattener to M48 imaging trains Designed specifically for the William Optics Gran...

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$68.00 USD
$64.60 USD
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$59.00 USD
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$56.05 USD
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William Optics 75mm -110mm Bahtinov Focusing Mask

Fits Telescope Dew Shields from 75mm to 110mm Creates Sharp Diffraction Spikes for Precise Focusing Ideal for Small Apochromatic Refractors and As...

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$59.00 USD
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$116.00 USD
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$110.20 USD
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$110.20 USD

William Optics 90° Erect Prism - 1.25"

Provides a fully corrected, upright, and non-reversed image Designed for 1.25" focusers and eyepieces 90° viewing angle for comfortable observing ...

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$116.00 USD
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$116.00 USD
$110.20 USD
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$138.00 USD
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$131.10 USD
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William Optics 99% Dielectric Dura Bright Diagonal - 1.25"

1.25" Barrel Diameter 99% Dielectric Coated Mirror 1/12λ Mirror Surface Accuracy 12mm Thick Mirror Substrate 100% Real Carbon Fiber Side Plates ...

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$138.00 USD
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$138.00 USD
$131.10 USD
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$158.00 USD
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$150.10 USD
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William Optics 99% Dielectric Dura Bright Diagonal - 2"

2" Barrel with 90° Viewing Angle 99% Reflectivity Dielectric Coatings 1/12th Wave Precision Polished Mirror 12mm Thick Mirror Substrate for Therma...

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$158.00 USD
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$158.00 USD
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$278.00 USD
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$278.00 USD
$264.10 USD
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William Optics Adjustable Flat61 for Z61

1.0x Flattener Power Designed for William Optics Zenithstar 61 Full-Frame Sensor Coverage Adjustable Back Focus Mechanism M54 Telescope Thread &am...

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$278.00 USD
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$278.00 USD
$264.10 USD
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$269.00 USD
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$269.00 USD
$255.55 USD
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William Optics Adjustable Flat6AIII

0.8x Focal Reducer & Field Flattener Optimized for GT71, GT81, Z81 & Z103 Refractors Illuminates Full-Frame Sensors Adjustable Back Focus ...

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$269.00 USD
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$269.00 USD
$255.55 USD
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$348.00 USD
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$330.60 USD
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William Optics Adjustable Flat6AIII for FLT91

Dedicated Field Flattener for the William Optics FLT91 Telescope Corrects Field Curvature for Pinpoint Stars Edge-to-Edge Integrated Adjustment Ri...

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$348.00 USD
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$348.00 USD
$330.60 USD
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$278.00 USD
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$264.10 USD
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William Optics Adjustable Flat73A for Z73

Designed specifically for the William Optics ZenithStar 73 APO Delivers a 1.0x, perfectly flat field across full-frame sensors Connects to the Z73...

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$278.00 USD
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$264.10 USD
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$284.00 USD
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$284.00 USD
$269.80 USD
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William Optics Adjustable Reducer Flattener Flat61R for Z61

Adjustable reducer and field flattener for William Optics Z61 telescope Improves image sharpness and reduces distortion Description ...

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$284.00 USD
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$284.00 USD
$269.80 USD
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$284.00 USD
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William Optics Adjustable Reducer Flattener Flat73R for Z73

Reduces focal length by a factor of 0.8x Designed for the William Optics Zenithstar 73 telescope Provides edge-to-edge flat field for full-frame s...

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$284.00 USD
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$284.00 USD
$269.80 USD
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$102.00 USD - $118.00 USD
$102.00 USD
$96.90 USD - $112.10 USD
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$96.90 USD

William Optics Bahtinov Mask Cover for GT71 / Z73 / Star71II

Patented Bahtinov mask integrated into a dust cover Precision-cut pattern for accurate focusing Designed for William Optics GT71, Z73, and Star71I...

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$102.00 USD - $118.00 USD
$102.00 USD
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$113.00 USD
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$113.00 USD
$107.35 USD
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$107.35 USD

William Optics Bahtinov Mask Cover for GT81 / Z81

Bahtinov mask cover for William Optics GT81 and Z81 telescopes Enhances focusing accuracy for astrophotography Description The Willi...

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$113.00 USD
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$113.00 USD
$107.35 USD
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$107.35 USD
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$185.00 USD
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$185.00 USD
$175.75 USD
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$175.75 USD

William Optics Bahtinov Mask Cover for Takahashi FSQ106

Bahtinov mask cover for Takahashi FSQ106 telescope Enhances focusing accuracy for astrophotography Description The William Optics Ba...

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$185.00 USD
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$175.75 USD
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$369.00 USD
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$350.55 USD
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William Optics Binoviewer Complete Package

Includes two 20mm 66° wide-angle eyepieces High-quality BaK4 prisms with full multi-coatings Large 20mm clear prism aperture prevents vignetting I...

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$369.00 USD
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$369.00 USD
$350.55 USD
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$129.00 USD
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$129.00 USD
$122.55 USD
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$122.55 USD

William Optics Camera Angle Rotator for 2.5" M63 Focuser

Adds 360° of smooth camera rotation Designed for William Optics 2.5" focusers Secure M63 male and female threads Maintains optical alignment durin...

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$129.00 USD
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$122.55 USD
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$249.00 USD
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$249.00 USD
$236.55 USD
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$236.55 USD

William Optics Carry Soft Case for FLT132

Designed specifically for the William Optics FLT132 refractor Ensures a precise, secure fit for the optical tube Soft-sided construction for light...

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$249.00 USD
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$249.00 USD
$236.55 USD
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$60.00 USD
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$57.00 USD
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William Optics Cat 51 Handle Bar

Length: 107 mm Integrated Mini-Vixen Style Saddle Weight: 0.12 kg / 0.26 lbs Designed for the William Optics Cat 51 Adds a carrying handle and acc...

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What Goes on Sale and Why

Understanding why an item is discounted helps you judge whether it is the right purchase, so we are explicit about the reason wherever we can be.

  • Open-box and display units: Returned or demonstrated equipment that has been inspected and tested here, typically indistinguishable from new in use.
  • Superseded models: Products replaced by a newer revision, often with only minor changes and full parts and warranty support remaining.
  • Overstock: Items we hold more of than current demand justifies, discounted while the stock lasts.
  • Seasonal accessories: Dew control, cases and cold-weather items that move seasonally and are reduced outside their peak.
  • End-of-line accessories: Adapters, rings and small parts from lines being retired, which remain perfectly serviceable.
  • Used equipment: Our separate collection of tested second-hand gear, for buyers comfortable with pre-owned optics and mounts.

Why Choose David Astro for Discounted Astronomy Gear

A discount is only a good deal if the item is right for your setup and stays supported afterwards.

  • Compatibility checked before you commit: We will confirm a sale item actually fits your telescope or mount, because a bargain adapter that does not fit is not a bargain.
  • Condition stated honestly: Open-box and display items are described as what they are, with any cosmetic marks noted.
  • Full warranty on new items: Discounted new stock carries the same manufacturer warranty as anything else we sell, handled domestically.
  • Canadian stock: Sale items ship from Canada without duties or brokerage fees for Canadian buyers.
  • Same support after the sale: Setup help, spacing calculations and in-house diagnostics apply to discounted purchases too.

Astronomy Sales in Canada — Frequently Asked Questions

Do sale items carry a warranty?
New discounted items carry the full manufacturer warranty. Open-box items are covered as stated on the listing, and we handle any claim domestically rather than routing it internationally.
Is an open-box item risky?
Not in our experience. Everything is inspected and functionally tested here before it is relisted, and anything with a cosmetic mark is described. Optics are checked for coating condition and collimation.
Can I still get support on a discontinued model?
Generally yes. We stock spare parts and adapters for many superseded models, and we say on the listing where parts availability is limited.
How long do sale prices last?
Until the stock is gone. These are finite quantities rather than a recurring promotion, so an item that disappears from this collection has usually sold rather than returned to full price.

Found something here?

Ask us before you order and we will confirm it fits your setup. Canadian stock, full support.