Skip to content
Price match 30-day returns* Talk to an astronomer before you buy

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.

Filters

William Optics M54 Camera Angle Rotator (CAA) Save 5% Save %
CA$164.00
CA$164.00 - CA$164.00
CA$164.00
CA$156.00
CA$156.00 - CA$156.00
CA$156.00

William Optics M54 Camera Angle Rotator (CAA)

360° of precise framing rotation Standard M54 male and female threads Adds a minimal 30.2 mm to the optical path Securely locks orientation for lo...

View full details
CA$164.00
CA$164.00 - CA$164.00
CA$164.00
CA$156.00
CA$156.00 - CA$156.00
CA$156.00
Save 5% Save %
Save 5% Save %
CA$66.00
CA$66.00 - CA$66.00
CA$66.00
CA$63.00
CA$63.00 - CA$63.00
CA$63.00

William Optics M63 Female to 2" Push-in Adapter for P-FLAT6AIII

Connects P-FLAT6AIII Flattener to 2" Focuser Female M63 Threads for Flattener Connection Male 2" Push-in Barrel for Focuser Internal M48 Female Th...

View full details
CA$66.00
CA$66.00 - CA$66.00
CA$66.00
CA$63.00
CA$63.00 - CA$63.00
CA$63.00
Save 5% Save %
Save 5% Save %
CA$92.00
CA$92.00 - CA$92.00
CA$92.00
CA$87.00
CA$87.00 - CA$87.00
CA$87.00

William Optics M63(F) to M48(M) Photo Adapter

Adds 80mm of Optical Length Connects to M63 Female Threads Outputs to M48 Male T-Threads Enables Focus Without a Field Flattener Designed for Will...

View full details
CA$92.00
CA$92.00 - CA$92.00
CA$92.00
CA$87.00
CA$87.00 - CA$87.00
CA$87.00
Save 5% Save %
William Optics M92 to M63 Adapter for William Optics FLT91 Save 5% Save %
CA$121.00
CA$121.00 - CA$121.00
CA$121.00
CA$115.00
CA$115.00 - CA$115.00
CA$115.00

William Optics M92 to M63 Adapter for William Optics FLT91

Connects William Optics FLT91 Telescope to Flat6AIII Flattener Input Thread: M92 Male Output Thread: M63 Female Optical Path Length: 10.5 mm De...

View full details
CA$121.00
CA$121.00 - CA$121.00
CA$121.00
CA$115.00
CA$115.00 - CA$115.00
CA$115.00
Save 5% Save %
Save 5% Save %
CA$65.00
CA$65.00 - CA$65.00
CA$65.00
CA$62.00
CA$62.00 - CA$62.00
CA$62.00

William Optics Micro 4/3 48mm T-Mount for Olympus - Black

Connects M48 Correctors to Olympus Micro 4/3 Cameras Fixed 35.6 mm Optical Length for Precise Back Focus Light-In Connection: M48 (Female) Thread ...

View full details
CA$65.00
CA$65.00 - CA$65.00
CA$65.00
CA$62.00
CA$62.00 - CA$62.00
CA$62.00
Save 5% Save %
William Optics Mighty Cat 71 f/3.2 Petzval Astrograph
William Optics Mighty Cat 71 f/3.2 Petzval Astrograph
Save 5% Save %
CA$3,497.00
CA$3,497.00 - CA$3,497.00
CA$3,497.00
CA$3,322.00
CA$3,322.00 - CA$3,322.00
CA$3,322.00

William Optics Mighty Cat 71 f/3.2 Petzval Astrograph

71mm Aperture, 230mm Focal Length, f/3.2 43.2mm Full-Frame Image Circle 7-Element EVO Optical Design with Super ED Glass WIFD Internal Rack and Pi...

View full details
CA$3,497.00
CA$3,497.00 - CA$3,497.00
CA$3,497.00
CA$3,322.00
CA$3,322.00 - CA$3,322.00
CA$3,322.00
Save 5% Save %
Save 10% Save %
CA$1,363.00
CA$1,363.00 - CA$1,363.00
CA$1,363.00
CA$1,227.00
CA$1,227.00 - CA$1,227.00
CA$1,227.00

William Optics MiniCat 51 WIFD f/3.5

51mm Aperture Diameter 178mm Focal Length f/3.5 Focal Ratio 6-Element Petzval Optical Design 43.2mm Full-Frame Image Circle WIFD Rack & Pinion...

View full details
CA$1,363.00
CA$1,363.00 - CA$1,363.00
CA$1,363.00
CA$1,227.00
CA$1,227.00 - CA$1,227.00
CA$1,227.00
Save 10% Save %
Save 5% Save %
CA$130.00
CA$130.00 - CA$130.00
CA$130.00
CA$124.00
CA$124.00 - CA$124.00
CA$124.00

William Optics Mortar Pier Head Adapter - 3/8" Screw Mount

Adapts the Mortar pier head to a mount with a 3/8" thread. 3/8" mount thread 2-year warranty Description Warranty The William O...

View full details
CA$130.00
CA$130.00 - CA$130.00
CA$130.00
CA$124.00
CA$124.00 - CA$124.00
CA$124.00
Save 5% Save %
Save 5% Save %
CA$109.00
CA$109.00 - CA$109.00
CA$109.00
CA$104.00
CA$104.00 - CA$104.00
CA$104.00

William Optics Mounting Ring and CAT Handle Bar Kit for ZenithStar 61 Version I

Allows for simple installation Made with improved CNC for greater rigidity Description The William Optics ZenithStar V1 Upgrade Mounting Rin...

View full details
CA$109.00
CA$109.00 - CA$109.00
CA$109.00
CA$104.00
CA$104.00 - CA$104.00
CA$104.00
Save 5% Save %
William Optics Mounting Ring for Z61
Save 5% Save %
CA$137.00
CA$137.00 - CA$137.00
CA$137.00
CA$130.00
CA$130.00 - CA$130.00
CA$130.00

William Optics Mounting Ring for Z61

Designed specifically for the William Optics ZenithStar 61 I Provides a secure, rigid mounting point for the optical tube Features an integrated C...

View full details
CA$137.00
CA$137.00 - CA$137.00
CA$137.00
CA$130.00
CA$130.00 - CA$130.00
CA$130.00
Save 5% Save %
Save 5% Save %
CA$246.00
CA$246.00 - CA$246.00
CA$246.00
CA$234.00
CA$234.00 - CA$234.00
CA$234.00

William Optics Mounting Rings 90mm

Precise 90mm Inner Diameter Solid, All-Metal Construction Secures Optical Tube for Astrophotography Requires User Measurement for Fit Confirmation...

View full details
CA$246.00
CA$246.00 - CA$246.00
CA$246.00
CA$234.00
CA$234.00 - CA$234.00
CA$234.00
Save 5% Save %
Save up to 6% Save %
CA$42.00 - CA$52.00
CA$42.00
CA$40.00 - CA$49.00
CA$40.00 - CA$49.00
CA$40.00

William Optics Pair of Riser Blocks

Provides critical clearance for cameras and filter wheels Improves balance options for complex imaging trains Made in versions for specific Willia...

View full details
CA$42.00 - CA$52.00
CA$42.00
CA$40.00 - CA$49.00
CA$40.00 - CA$49.00
CA$40.00
Save up to 6% Save %
Save 5% Save %
CA$1,488.00
CA$1,488.00 - CA$1,488.00
CA$1,488.00
CA$1,414.00
CA$1,414.00 - CA$1,414.00
CA$1,414.00

William Optics Pier Mount 90

90 kg (198 lbs) Loading Capacity Lightweight 7 kg Aluminum Alloy Construction 100 mm (4") Diameter Pillar for Maximum Rigidity Includes 3/8" Adapt...

View full details
CA$1,488.00
CA$1,488.00 - CA$1,488.00
CA$1,488.00
CA$1,414.00
CA$1,414.00 - CA$1,414.00
CA$1,414.00
Save 5% Save %
Save 5% Save %
CA$5,793.00
CA$5,793.00 - CA$5,793.00
CA$5,793.00
CA$5,503.00
CA$5,503.00 - CA$5,503.00
CA$5,503.00

William Optics Pleiades 111 Astrograph F/4.8 7-element WIFD

111mm Aperture 7-Element Astrograph 528mm Focal Length at a fast f/4.8 45mm Image Circle for Full-Frame Sensors William Optics Internal Focus Desi...

View full details
CA$5,793.00
CA$5,793.00 - CA$5,793.00
CA$5,793.00
CA$5,503.00
CA$5,503.00 - CA$5,503.00
CA$5,503.00
Save 5% Save %
Save 5% Save %
CA$27,597.00
CA$27,597.00 - CA$27,597.00
CA$27,597.00
CA$26,217.00
CA$26,217.00 - CA$26,217.00
CA$26,217.00

William Optics Pleiades 181 Astrograph F/5.5 7-element with 3 ED glasses

181mm Aperture 998mm Focal Length (f/5.5) 7-Element Optical Design with 3 Super ED Glass Elements 55mm Corrected Image Circle 4.1-inch Rack & ...

View full details
CA$27,597.00
CA$27,597.00 - CA$27,597.00
CA$27,597.00
CA$26,217.00
CA$26,217.00 - CA$26,217.00
CA$26,217.00
Save 5% Save %
Save 5% Save %
CA$3,033.00
CA$3,033.00 - CA$3,033.00
CA$3,033.00
CA$2,881.00
CA$2,881.00 - CA$2,881.00
CA$2,881.00

William Optics Pleiades 68 Astrograph F/3.8 7-Element WIFD

68mm Aperture 7-Element Astrograph Fast f/3.8 Focal Ratio 260mm Focal Length 48mm Full-Frame Image Circle 2.98 kg (6.57 lbs) Optical Tube Patented...

View full details
CA$3,033.00
CA$3,033.00 - CA$3,033.00
CA$3,033.00
CA$2,881.00
CA$2,881.00 - CA$2,881.00
CA$2,881.00
Save 5% Save %
Save 5% Save %
CA$1,161.00
CA$1,161.00 - CA$1,161.00
CA$1,161.00
CA$1,103.00
CA$1,103.00 - CA$1,103.00
CA$1,103.00

William Optics RC Focuser w/ Optional 0.8x RC Reducer Flattener

Focuser for 12 to 16 inch William Optics and GSO Ritchey-Chrétien telescopes Optional 0.8x RC reducer flattener, not included (William Optics of...

View full details
CA$1,161.00
CA$1,161.00 - CA$1,161.00
CA$1,161.00
CA$1,103.00
CA$1,103.00 - CA$1,103.00
CA$1,103.00
Save 5% Save %
Save 5% Save %
CA$122.00
CA$122.00 - CA$122.00
CA$122.00
CA$116.00
CA$116.00 - CA$116.00
CA$116.00

William Optics Red Dot Finder Kit with Vixen Style Mounting Base

Red dot finder for easy target acquisition Includes Vixen-style mounting base for versatile attachment Description The William...

View full details
CA$122.00
CA$122.00 - CA$122.00
CA$122.00
CA$116.00
CA$116.00 - CA$116.00
CA$116.00
Save 5% Save %
Save 5% Save %
CA$1,225.00
CA$1,225.00 - CA$1,225.00
CA$1,225.00
CA$1,164.00
CA$1,164.00 - CA$1,164.00
CA$1,164.00

William Optics Redcat 51 WIFD

51mm Aperture 250mm Focal Length (f/4.9) 4-Element Petzval-like Optical Design 45mm Full-Frame Image Circle William Optics Internal Focus Design (...

View full details
CA$1,225.00
CA$1,225.00 - CA$1,225.00
CA$1,225.00
CA$1,164.00
CA$1,164.00 - CA$1,164.00
CA$1,164.00
Save 5% Save %
Save 5% Save %
CA$1,581.00
CA$1,581.00 - CA$1,581.00
CA$1,581.00
CA$1,502.00
CA$1,502.00 - CA$1,502.00
CA$1,502.00

William Optics RedCat 61 WIFD

61mm Aperture f/4.9 Focal Ratio / 300mm Focal Length 4-Element Petzval-like Optical Design with FPL-53 Glass 45mm Full-Frame Corrected Image Circl...

View full details
CA$1,581.00
CA$1,581.00 - CA$1,581.00
CA$1,581.00
CA$1,502.00
CA$1,502.00 - CA$1,502.00
CA$1,502.00
Save 5% Save %
Save 5% Save %
CA$2,013.00
CA$2,013.00 - CA$2,013.00
CA$2,013.00
CA$1,912.00
CA$1,912.00 - CA$1,912.00
CA$1,912.00

William Optics Redcat 71 WIFD

71mm Aperture Petzval-like Astrograph 350mm Focal Length at f/4.9 45mm Flat-Field Image Circle (Full-Frame) 4-Element Design with FPL-53 G...

View full details
CA$2,013.00
CA$2,013.00 - CA$2,013.00
CA$2,013.00
CA$1,912.00
CA$1,912.00 - CA$1,912.00
CA$1,912.00
Save 5% Save %
Save 5% Save %
CA$219.00
CA$219.00 - CA$219.00
CA$219.00
CA$208.00
CA$208.00 - CA$208.00
CA$208.00

William Optics RedCat WIFD Erecting Prism - 1.25"

Converts Astronomical Telescopes for Terrestrial Viewing 90-Degree Viewing Angle Accepts Standard 1.25" Eyepieces Anti-Reflection Coated BAK7 Pris...

View full details
CA$219.00
CA$219.00 - CA$219.00
CA$219.00
CA$208.00
CA$208.00 - CA$208.00
CA$208.00
Save 5% Save %
Save 5% Save %
CA$109.00
CA$109.00 - CA$109.00
CA$109.00
CA$104.00
CA$104.00 - CA$104.00
CA$104.00

William Optics Saddle Plate for Vixen-Style Dovetail Plate - 90mm

Length: 90 mm Dovetail Type: Vixen-Style Weight: 230 g (0.51 lbs) Full-Length, Non-Marring Clamp Signature William Optics Red Anodized Finish D...

View full details
CA$109.00
CA$109.00 - CA$109.00
CA$109.00
CA$104.00
CA$104.00 - CA$104.00
CA$104.00
Save 5% Save %
Save 5% Save %
CA$62.00
CA$62.00 - CA$62.00
CA$62.00
CA$59.00
CA$59.00 - CA$59.00
CA$59.00

William Optics SCT Connection for WO Diagonals - Gold

Connects a 2" SCT Thread to a William Optics 2" Diagonal Adds 13.8 mm of Optical Length Female Thread: M50.8 Male Thread: M48 Signature William Op...

View full details
CA$62.00
CA$62.00 - CA$62.00
CA$62.00
CA$59.00
CA$59.00 - CA$59.00
CA$59.00
Save 5% Save %

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.
  • 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.