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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.

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William Optics 1.25" 90° Erect Prism for Cat 61 WIFD
$159.00 - $159.00
$159.00
$159.00 - $159.00
$159.00

William Optics 1.25" 90° Erect Prism for Cat 61 WIFD

WO-D-EP90-125-RC61
1 in stock

Provides a fully corrected, erect image for terrestrial viewing Comfortable 90° viewing angle Standard 1.25" barrel accepts most astronomical eyep...

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$159.00 - $159.00
$159.00
$159.00 - $159.00
$159.00
$159.00 - $159.00
$159.00
$159.00 - $159.00
$159.00

William Optics RedCat WIFD Erecting Prism - 1.25"

WO-D-EP90-125-RC51III
1 in stock

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

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$159.00 - $159.00
$159.00
$159.00 - $159.00
$159.00
$156.00 - $156.00
$156.00
$156.00 - $156.00
$156.00

William Optics SWAN 72° 40mm Eyepiece - 2"

WO-E-SWA40
4 in stock

40mm Focal Length 72° Apparent Field of View 2" Diameter Barrel 28mm Long Eye Relief Parfocal Design Description FAQ Specifications In the Box ...

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$156.00 - $156.00
$156.00
$156.00 - $156.00
$156.00
$148.00 - $178.00
$148.00 - $178.00
$148.00 - $178.00
$148.00

William Optics 50mm Guiding Scope

Options available
1 variants in stock

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 - $178.00
$148.00 - $178.00
$148.00 - $178.00
$148.00
$141.00 - $141.00
$141.00
$141.00 - $141.00
$141.00

William Optics 243mm Saddle Handle Bar with 50mm Guiding Rings

WO-M-HC243BL-GR50IISL

Compatible with William Optics' slide-base guide rings Can be used to make William Optics telescopes portable Description The Wil...

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$141.00 - $141.00
$141.00
$141.00 - $141.00
$141.00
$138.00 - $138.00
$138.00
$138.00 - $138.00
$138.00

William Optics STL Adapter for FLT Flattener

WO-P-STL

Connects SBIG STL-11000 Series CCD Cameras Attaches to P-FLAT68 Field Flatteners via M80 Female Thread Provides a Precise 69 mm Optical Path Lengt...

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$138.00 - $138.00
$138.00
$138.00 - $138.00
$138.00
$138.00 - $138.00
$138.00
$138.00 - $138.00
$138.00

William Optics 99% Dielectric Dura Bright Diagonal - 1.25"

WO-D-125D-C-DB
1 in stock

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 - $138.00
$138.00
$138.00 - $138.00
$138.00
$137.00 - $137.00
$137.00
$137.00 - $137.00
$137.00

William Optics Slide-Base UniGuide 32mm Scope

Options available
7 variants in stock

32mm Doublet Objective Lens Fast f/3.75 Focal Ratio 120mm Focal Length Integrated Vixen/Synta-Style Slide-Base Ultra-Lightweight at 0.23 kg (0.51 ...

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$137.00 - $137.00
$137.00
$137.00 - $137.00
$137.00
$129.00 - $129.00
$129.00
$129.00 - $129.00
$129.00

William Optics Camera Angle Rotator for 2.5" M63 Focuser

WO-M-CAA63
1 in stock

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 - $129.00
$129.00
$129.00 - $129.00
$129.00
$116.00 - $139.00
$116.00 - $139.00
$116.00 - $139.00
$116.00

William Optics Losmandy Style Type D

Options available
3 variants in stock

Length: 400 mm Weight: 1.44 kg / 3.17 lbs Width: 105 mm Dovetail Type: Losmandy D-Style Description FAQ Specifications In the Box Downloads War...

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$116.00 - $139.00
$116.00 - $139.00
$116.00 - $139.00
$116.00
William Optics M54 Camera Angle Rotator (CAA)
$119.00 - $119.00
$119.00
$119.00 - $119.00
$119.00

William Optics M54 Camera Angle Rotator (CAA)

WO-M-CAA54
1 in stock

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...

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$119.00 - $119.00
$119.00
$119.00 - $119.00
$119.00
$118.00 - $118.00
$118.00
$118.00 - $118.00
$118.00

William Optics 120mm Saddle Handle Bar with 50mm Guiding Rings

WO-M-HC120BL-GR50SL

120 mm Total Length Patented Handle and Saddle Design Mini-Vixen Dovetail Saddle Includes 50mm Guide Rings 44 mm Width Description FAQ Specific...

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$118.00 - $118.00
$118.00
$118.00 - $118.00
$118.00
$113.00 - $113.00
$113.00
$113.00 - $113.00
$113.00

William Optics Bahtinov Mask Cover for GT81 / Z81

Options available

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

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$113.00 - $113.00
$113.00
$113.00 - $113.00
$113.00
$116.00 - $116.00
$116.00
$116.00 - $116.00
$116.00

William Optics 90° Erect Prism - 1.25"

WO-D-EP90-125II
5 in stock

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 - $116.00
$116.00
$116.00 - $116.00
$116.00
$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00

William Optics SPL 55° 12.5mm Eyepiece - 1.25"

WO-E-SPL12.5

1.25-inch eyepiece with 55° apparent field of view 12.5mm focal length for medium-high magnification viewing Description The W...

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$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00
$110.00 - $110.00
$110.00
$110.00 - $110.00
$110.00

William Optics 45° Erecting Prism - 1.25"

WO-D-EP125
6 in stock

Provides a fully corrected image (upright and left-right correct) Comfortable 45° viewing angle for terrestrial observation Fits standard 1.25" fo...

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$110.00 - $110.00
$110.00
$110.00 - $110.00
$110.00
$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00

William Optics 243mm Saddle Handle Bar

WO-M-HC243BL
1 in stock

243mm total length Functions as both a carrying handle and an accessory saddle Patented design for rigidity and ergonomics Vixen-style saddle for ...

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$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00

William Optics Super High Precision COPPER T-Mount for Nikon Full Frame

WO-YE-TR-BR48-N

Solid Copper Construction for Maximum Rigidity M48 x 0.75 Female Thread for Wide-Field Correctors Designed for Nikon Full-Frame DSLR and Mirrorles...

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$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00

William Optics Super High Precision COPPER T-Mount for Canon EOS Full Frame

WO-YE-TR-BR48-C
1 in stock

Solid Copper Construction for Maximum Rigidity M48 (2") Female Thread for Wide-Field Correctors Connects to Canon EOS Camera Bodies Precise 10.6 m...

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$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00

William Optics 243-308mm Bahtinov Focusing Mask

WO-BM-DS-GR150

Fits Dew Shields with Outer Diameters from 243mm to 308mm Generates a Clear Three-Spike Diffraction Pattern for Precise Focusing Essential Tool fo...

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$108.00 - $108.00
$108.00
$108.00 - $108.00
$108.00
$102.00 - $118.00
$102.00 - $118.00
$102.00 - $118.00
$102.00

William Optics Bahtinov Mask Cover for GT71 / Z73 / Star71II

Options available

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 - $118.00
$102.00 - $118.00
$102.00 - $118.00
$102.00
$99.00 - $99.00
$99.00
$99.00 - $99.00
$99.00

William Optics 2" RotoLock Adapter - SCT

WO-D-ROTO-A2-SCT2F

Designed for Schmidt-Cassegrain Telescopes (SCT) Features a secure RotoLock mechanism for 2" accessories Description The Willi...

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$99.00 - $99.00
$99.00
$99.00 - $99.00
$99.00
$97.00 - $97.00
$97.00
$97.00 - $97.00
$97.00

William Optics 120mm Saddle Handle Bar with 50mm Guiding Rings - No Adjustments Screws

WO-M-HC120BL-GR50IISL

120 mm Length Integrated 50mm Guide Rings Mini-Vixen Style Top Saddle 44 mm Width Designed for Maximum Rigidity Description FAQ Specifications ...

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$97.00 - $97.00
$97.00
$97.00 - $97.00
$97.00
William Optics Mounting Ring for Z61
$99.00 - $99.00
$99.00
$99.00 - $99.00
$99.00

William Optics Mounting Ring for Z61

WO-M-R-61BL-P

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

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$99.00 - $99.00
$99.00
$99.00 - $99.00
$99.00

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.