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William Optics

William Optics

William Optics has built its reputation on small apochromatic astrographs that are genuinely portable, mechanically well finished and easy to bring to focus — the RedCat and Zenithstar families in particular have become default recommendations for imagers who want wide fields without a heavy mount. David Astro stocks William Optics products in Canada, shipping from Canadian inventory.

We image with these telescopes here, and can tell you where the fixed back-focus of the Petzval designs simplifies your life and where a longer focal length model would serve your targets better.

Filtres

CA$27,597.00 - CA$27,597.00
CA$27,597.00
CA$27,597.00 - CA$27,597.00
CA$27,597.00

William Optics Pleiades 181 Astrograph F/5.5 7 éléments avec 3 lunettes ED

WO-T-P-181RD

APO à 7 éléments avec conception de réfracteur à 3 lunettes ED Rapport focale rapide F/5,5 Portable et polyvalent Description Car...

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CA$27,597.00 - CA$27,597.00
CA$27,597.00
CA$27,597.00 - CA$27,597.00
CA$27,597.00
CA$10,653.00 - CA$12,417.00
CA$10,653.00 - CA$12,417.00
CA$10,653.00 - CA$12,417.00
CA$10,653.00

William Optics Fluorostar 156

Options available

APO de 156 mm Rapport focale rapide F/6,7 Portable et polyvalent Description Caractéristiques Dans la boite Libérez vot...

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CA$10,653.00 - CA$12,417.00
CA$10,653.00 - CA$12,417.00
CA$10,653.00 - CA$12,417.00
CA$10,653.00
William Optics Ultra-Cat 131 f/4.9 Petzval Astrograph
CA$7,449.00 - CA$7,449.00
CA$7,449.00
CA$7,449.00 - CA$7,449.00
CA$7,449.00

William Optics Ultra-Cat 131 f/4.9 Petzval Astrograph

WO-T-C-131BR

131mm Aperture 648mm Focal Length (f/4.9) 5-Element Advanced Petzval Optical Design 60mm Flat-Field Image Circle Patented WIFD Internal Focuser 13...

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CA$7,449.00 - CA$7,449.00
CA$7,449.00
CA$7,449.00 - CA$7,449.00
CA$7,449.00
CA$6,304.00 - CA$8,162.00
CA$6,304.00 - CA$8,162.00
CA$6,304.00 - CA$8,162.00
CA$6,304.00

William Optics Fluorostar 132

Options available

APO de 132 mm Rapport focale rapide F/6.9 Portable et polyvalent Description Caractéristiques Dans la boite Libérez vot...

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CA$6,304.00 - CA$8,162.00
CA$6,304.00 - CA$8,162.00
CA$6,304.00 - CA$8,162.00
CA$6,304.00
CA$5,793.00 - CA$5,793.00
CA$5,793.00
CA$5,793.00 - CA$5,793.00
CA$5,793.00

William Optics Pleiades 111 Astrographe F/4.8 7 éléments WIFD

WO-T-P-111BU

Conception du réfracteur APO à 7 éléments Rapport focale rapide F/4,8 Conception de champ d'image large (WIFD) Portable et polyvalent ...

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CA$5,793.00 - CA$5,793.00
CA$5,793.00
CA$5,793.00 - CA$5,793.00
CA$5,793.00
CA$5,517.00 - CA$5,517.00
CA$5,517.00
CA$5,517.00 - CA$5,517.00
CA$5,517.00

William Optics UltraCat 108 f/4.8 WIFD

WO-T-C-108BR
1 en stock

108mm Aperture, 5-Element Advanced Petzval Optical Design Fast f/4.8 Focal Ratio with 518mm Focal Length Massive 60mm Flat-Field Image Circle Pate...

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CA$5,517.00 - CA$5,517.00
CA$5,517.00
CA$5,517.00 - CA$5,517.00
CA$5,517.00
CA$4,965.00 - CA$4,965.00
CA$4,965.00
CA$4,965.00 - CA$4,965.00
CA$4,965.00

William Optics Fluorostar 120

Options available

120 mm APO Rapport focal rapide F/6 Portable et polyvalent Description Caractéristiques Dans la boite Libérez votre passio...

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CA$4,965.00 - CA$4,965.00
CA$4,965.00
CA$4,965.00 - CA$4,965.00
CA$4,965.00
CA$3,741.00 - CA$4,137.00
CA$3,741.00 - CA$4,137.00
CA$3,741.00 - CA$4,137.00
CA$3,741.00

William Optics Cat 91 WIFD

Options available
1 variants in stock

Lunette portable Petzval APO 51 mm f/4,9 Idéal pour l'astrophotographie du ciel profond à grand champ Cercle d'imagerie à champ plat plein f...

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CA$3,741.00 - CA$4,137.00
CA$3,741.00 - CA$4,137.00
CA$3,741.00 - CA$4,137.00
CA$3,741.00
CA$3,033.00 - CA$3,033.00
CA$3,033.00
CA$3,033.00 - CA$3,033.00
CA$3,033.00

William Optics UltraCat 76 f/4.8 WIFD

WO-T-C-76BR
2 en stock

76 mm Aperture, 365 mm Focal Length (f/4.8) 5-Element Advanced Petzval Optical Design 50 mm Corrected Image Circle William Optics Internal Focusin...

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CA$3,033.00 - CA$3,033.00
CA$3,033.00
CA$3,033.00 - CA$3,033.00
CA$3,033.00
CA$3,033.00 - CA$3,033.00
CA$3,033.00
CA$3,033.00 - CA$3,033.00
CA$3,033.00

William Optics Pleiades 68 Astrographe F/3.8 7 éléments WIFD

WO-T-P-68BU

Conception du réfracteur APO à 7 éléments Rapport focale rapide F/3,8 Conception du porte-oculaire interne WO (WIFD) Portable et polyvalent...

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CA$3,033.00 - CA$3,033.00
CA$3,033.00
CA$3,033.00 - CA$3,033.00
CA$3,033.00
CA$3,033.00 - CA$3,033.00
CA$3,033.00
CA$3,033.00 - CA$3,033.00
CA$3,033.00

William Optics Gran Turismo WIFD 81

Options available

APO de 81 mm Rapport focale rapide F/5.9 Portable et polyvalent Description Caractéristiques Dans la boite Libérez votr...

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CA$3,033.00 - CA$3,033.00
CA$3,033.00
CA$3,033.00 - CA$3,033.00
CA$3,033.00
CA$2,877.00 - CA$3,033.00
CA$2,877.00 - CA$3,033.00
CA$2,877.00 - CA$3,033.00
CA$2,877.00

William Optics Fluorostar 91

Options available

APO de 91 mm utilisant du verre FPL-53 Rapport focale rapide F/5.9 Portable et polyvalent Description Caractéristiques Dans la b...

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CA$2,877.00 - CA$3,033.00
CA$2,877.00 - CA$3,033.00
CA$2,877.00 - CA$3,033.00
CA$2,877.00
CA$2,013.00 - CA$2,013.00
CA$2,013.00
CA$2,013.00 - CA$2,013.00
CA$2,013.00

William Optics Redcat 71 WIFD

WO-T-C-71RDII

APO de 71 mm Rapport focale rapide F/4.9 Portable et polyvalent Description Caractéristiques Dans la boite Libérez votr...

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CA$2,013.00 - CA$2,013.00
CA$2,013.00
CA$2,013.00 - CA$2,013.00
CA$2,013.00
CA$1,929.00 - CA$1,929.00
CA$1,929.00
CA$1,929.00 - CA$1,929.00
CA$1,929.00

William Optics UltraCat 56 f/4.8 WIFD

WO-T-C-56BR
6 en stock

56mm Aperture, 269mm Focal Length (f/4.8) 5-Element Advanced Petzval Optical Design 50mm Image Circle for Full-Frame Sensors William Optics Intern...

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CA$1,929.00 - CA$1,929.00
CA$1,929.00
CA$1,929.00 - CA$1,929.00
CA$1,929.00
CA$1,581.00 - CA$1,581.00
CA$1,581.00
CA$1,581.00 - CA$1,581.00
CA$1,581.00

William Optics RedCat 61 WIFD

WO-T-C-61RD
1 en stock

Lunette Petzval 51 mm à 4 éléments Focale de 300 mm - rapport focal f/4,9 Cercle d'image de 46 mm - Aucun aplatisseur de champ requis C...

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CA$1,581.00 - CA$1,581.00
CA$1,581.00
CA$1,581.00 - CA$1,581.00
CA$1,581.00
CA$1,515.00 - CA$1,515.00
CA$1,515.00
CA$1,515.00 - CA$1,515.00
CA$1,515.00

William Optics Gran Turismo 71 Triplet APO

WO-A-F71GTII-RD

Triplet APO de 71 mm Rapport focale rapide F/5.9 Portable et polyvalent Description Caractéristiques Dans la boite Libé...

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CA$1,515.00 - CA$1,515.00
CA$1,515.00
CA$1,515.00 - CA$1,515.00
CA$1,515.00
CA$1,488.00 - CA$1,488.00
CA$1,488.00
CA$1,488.00 - CA$1,488.00
CA$1,488.00

William Optics Pier Mount 90

WO-YG-PM-90R

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

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CA$1,488.00 - CA$1,488.00
CA$1,488.00
CA$1,488.00 - CA$1,488.00
CA$1,488.00
William Optics Ultra Flat 156 (0.79x Reducer)
CA$1,474.00 - CA$1,474.00
CA$1,474.00
CA$1,474.00 - CA$1,474.00
CA$1,474.00

William Optics Ultra Flat 156 (0.79x Reducer)

WO-P-FLAT-156

Reduces focal ratio by a factor of 0.79x Designed for Medium Format, Full Frame, and APS-C sensors 3-element, 3-group optical design Requires 75.5...

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CA$1,474.00 - CA$1,474.00
CA$1,474.00
CA$1,474.00 - CA$1,474.00
CA$1,474.00
William Optics Ultra Flat 132 (0.79x Reducer)
CA$1,474.00 - CA$1,474.00
CA$1,474.00
CA$1,474.00 - CA$1,474.00
CA$1,474.00

William Optics Ultra Flat 132 (0.79x Reducer)

WO-P-FLAT-132

Reduces focal ratio by a factor of 0.79x Provides a flat field for Full Frame, APS-C, and M4/3 sensors 3-element, 3-group optical design Connects ...

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CA$1,474.00 - CA$1,474.00
CA$1,474.00
CA$1,474.00 - CA$1,474.00
CA$1,474.00
CA$1,398.00 - CA$1,515.00
CA$1,398.00 - CA$1,515.00
CA$1,398.00 - CA$1,515.00
CA$1,398.00

William Optics Zenithstar 81 WIFD Telescope

Options available

Patented William Optics Internal Focus Design (WIFD) Rigid M92 Rear Thread with M63 Adapter Included Vixen/Arca-Swiss Dual-Sided Mounting Plate In...

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CA$1,398.00 - CA$1,515.00
CA$1,398.00 - CA$1,515.00
CA$1,398.00 - CA$1,515.00
CA$1,398.00
CA$1,363.00 - CA$1,363.00
CA$1,363.00
CA$1,363.00 - CA$1,363.00
CA$1,363.00

William Optics MiniCat 51 WIFD f/3.5

WO-T-C-MINI-RD
3 en stock

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...

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CA$1,363.00 - CA$1,363.00
CA$1,363.00
CA$1,363.00 - CA$1,363.00
CA$1,363.00
CA$1,225.00 - CA$1,225.00
CA$1,225.00
CA$1,225.00 - CA$1,225.00
CA$1,225.00

William Optics Redcat 51 WIFD

WO-L-RC51RDIII
1 en stock

Lunette Petzval 51 mm à 4 éléments Distance focale de 250 mm - rapport focal f/4,9 Cercle d'image de 48 mm - Aucun aplatisseur de champ requi...

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CA$1,225.00 - CA$1,225.00
CA$1,225.00
CA$1,225.00 - CA$1,225.00
CA$1,225.00
CA$1,161.00 - CA$1,161.00
CA$1,161.00
CA$1,161.00 - CA$1,161.00
CA$1,161.00

William Optics Porte-Oculaire RC avec Aplanisseur / Réducteur RC 0,8x en option

Options available

Fournit une mise au point précise pour les télescopes Ritchey-Chrétien Comprend un aplatisseur de réduction 0,8x en option pour une qualité d'i...

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CA$1,161.00 - CA$1,161.00
CA$1,161.00
CA$1,161.00 - CA$1,161.00
CA$1,161.00
CA$1,161.00 - CA$1,161.00
CA$1,161.00
CA$1,161.00 - CA$1,161.00
CA$1,161.00

William Optics Aplanisseur / Réducteur 0.72x FLAT8

WO-P-FLAT8

Réducteur/aplatisseur 0,72x pour télescopes réfracteurs William Optics Réduit la distance focale et corrige la courbure du champ pour une...

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CA$1,161.00 - CA$1,161.00
CA$1,161.00
CA$1,161.00 - CA$1,161.00
CA$1,161.00

The William Optics Range

The line divides fairly cleanly between Petzval astrographs with built-in field correction and traditional doublets and triplets that use a separate flattener.

  • RedCat and Petzval astrographs: Four-element designs with the flattener integrated, giving a flat field at a fixed back-focus with no spacing calculation required — the simplest imaging optics to set up correctly.
  • Zenithstar apochromatic refractors: Compact FPL-53 doublets from 61 mm upward, popular as first imaging telescopes and as guide or companion scopes on larger rigs.
  • GT and FLT triplet refractors: Larger apochromatic triplets for imagers who want more aperture and focal length while keeping a refractor's convenience.
  • UniGuide guide scopes: Rigid guide scopes with integrated mounting that avoids the flexure common to ring-and-bracket guide setups.
  • RotoLock and mechanical accessories: Rotating locking collars, dovetails, tube rings and Bahtinov masks designed to fit the tubes precisely.
  • Diagonals and eyepieces: Dielectric diagonals and eyepiece lines matched to the refractors for visual use.

Why Choose David Astro for William Optics

These telescopes are straightforward to use and easy to buy in the wrong focal length. That is where the advice matters.

  • Focal length matched to targets: We calculate the field of view your sensor will get on each model, so you can see whether your target actually fits before ordering.
  • Petzval back-focus supplied: The integrated designs have a fixed spacing requirement, and we provide the exact adapter list for your camera and filter setup.
  • Authorized dealer: Full manufacturer warranty with verified authenticity, handled domestically in Canada.
  • Canadian stock: Ships from Canada with no duties or brokerage fees for Canadian orders.
  • Support after first light: Help diagnosing tilt, spacing and star shape once the telescope is on the sky.

William Optics in Canada — Frequently Asked Questions

Do RedCat telescopes need a flattener?
No. The Petzval design includes field correction, so you only need to hit the specified back-focus to the camera sensor. That is one of the main reasons they are recommended to first-time imagers.
Which focal length should I choose?
It depends on your target size and sensor. Around 250 mm suits large nebulae and the Andromeda galaxy; 400 to 600 mm frames most emission nebulae well; beyond that you are into small galaxies and planetary nebulae, which also demands better guiding.
Can these work as guide scopes?
The smaller Zenithstars and the UniGuide range are commonly used this way. The key advantage of a purpose-built guide scope is rigidity — a flexing guide scope produces errors that guiding cannot correct.
Is warranty handled in Canada?
Yes. As an authorized dealer we process warranty and service claims here, without international shipping or customs paperwork.

Choosing a focal length?

Send us your camera and your target list and we will show you the framing. Canadian stock, full warranty.