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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" RotoLock Visual Back Adapter - SCT

WO-F-ROTO-A2-125-SCT-TA

Securely holds 1.25" eyepieces and accessories RotoLock system provides self-centering, even grip Attaches to standard SCT rear threads (M50.8 fem...

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William Optics Long Version Vixen-Style Dovetail Plate

WO-M-PV-LII-RD
2 in stock

290 mm Extended Length for Balancing Standard Vixen-Style Dovetail Profile Weighs 0.64 kg (1.42 lbs) 90 mm Wide Platform for Stability Descript...

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

WO-YG-38-MTAD-BL

Designed to fit a 3/8" threaded pier. Universal 3/8" thread Limited lifetime warranty Description Warranty The William Optics M...

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William Optics 2" RotoLock - M63

WO-F-ROTO-A63SL

2" RotoLock adapter designed for M63 threads Ensures a secure and precise connection for 2" accessories ...

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William Optics Red Dot Finder Kit with Vixen Style Mounting Base

WO-M-RDF-P-VBII
7 in stock

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

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$85.00 - $85.00
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William Optics M92 to M63 Adapter for William Optics FLT91
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William Optics M92 to M63 Adapter for William Optics FLT91

WO-YE-M92-63

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

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William Optics 172mm -235mm Bahtinov Focusing Mask

WO-BM-DS-GR90

Fits Dew Shield Diameters from 172mm to 235mm Generates Clear Diffraction Spikes for Precise Focusing Ideal for Astrophotography of Planets and De...

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William Optics Vixen Style Finder Mounting Bracket for RedCat - Black Base

WO-M-FB50-RC-BB

Seamlessly integrate with your existing astrophotography gear. Ensures stable attachment of your telescope to your mount. Description In th...

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$80.00 - $80.00
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William Optics Saddle Plate for Vixen-Style Dovetail Plate - 90mm

WO-M-SP90RC-RD
1 in stock

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...

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William Optics ZenithStar V1 Upgrade Mounting Ring

Options available

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

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$76.00 - $76.00
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William Optics Slide-Base 50mm Guiding Rings

WO-M-GR50SL
1 in stock

Securely holds guidescopes and finders with a 50mm tube diameter Slide-base design allows for fore-and-aft adjustment for precise balancing Essent...

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William Optics Vixen Style Finder Mounting Bracket

WO-M-FB50-B
1 in stock

Vixen-Style Dovetail Base Secure Mounting for Finderscopes and Guide Scopes Durable Metal Construction Compatible with Most Telescope Optical Tube...

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William Optics 4" Extender for FLT Series
$68.00 - $68.00
$68.00
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$68.00

William Optics 4" Extender for FLT Series

WO-P-M92EX

Adds 67 mm of optical length to your imaging train Features M92 male and female threads for a secure connection Designed for William Optics FLT 11...

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William Optics 54mm Flattener Extender for GT81 WIFD
$68.00 - $68.00
$68.00
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$68.00

William Optics 54mm Flattener Extender for GT81 WIFD

WO-AD-M80-54-M48

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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William Optics 48mm T-Mount for Canon EOS R Mirrorless

WO-TM-CN-EOSR-M48
3 in stock

Connects M48-threaded correctors to Canon EOS R mirrorless cameras Wide 48mm aperture minimizes vignetting on full-frame sensors Precisely machine...

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William Optics 48mm T-Mount for Nikon Z

WO-TM-NK-Z-M48

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

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William Optics 105 -148mm Bahtinov Focusing Mask

WO-BM-DS-GR55

Fits Telescope Dew Shields from 105mm to 148mm Generates Clear Diffraction Spikes for Focusing Removes Subjectivity from Manual Focusing Lightweig...

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William Optics Slide-Base 50mm Guiding Rings - No Adjustments Screws

WO-M-GR50IISL

Seamlessly integrate with your existing astrophotography gear. Ensures stable attachment of your telescope to your mount. Description In th...

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$64.00 - $64.00
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William Optics M63(M) to M48(M) Photo Adapter

WO-P-PAM-63-48

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...

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William Optics 4" Extension Tube for FLT Series

WO-P-EXFLT

4" extension tube designed for William Optics FLT Series Provides additional back focus for various optical setups ...

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William Optics Flat4 Draw Tube Adapter for FLT (Gold) for 2007-2016 Models

WO-AD4-A006-L00GD03

Securely connects the Flat4 Field Flattener to the draw tube Designed for William Optics FLT 98, 110, 132, and 152 models Compatible with telescop...

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William Optics Flat4 Draw Tube Adapter for GT102, FLT 132 - Blue for 3" V-power Focuser

WO-AD4-A006-L00BU03

Connects Flat4 Flattener to 3" V-Power Focuser Compatible with William Optics GT102 & FLT 132 Engineered for 2017 Telescope Models Secure Thre...

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William Optics Flat4 Draw Tube Adapter for GT102, FLT 132 - Black for 3" V-Power Focuser

WO-AD4-A006-L00BL03

Connects William Optics Flat4 Flattener to Draw Tube Designed for the 3" V-Power Focuser Compatible with GT102 & FLT 132 (2017 Models) Ensures...

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William Optics Cat Series Saddle Handle Bar

Options available
3 variants in stock

Length: 107 mm Integrated Mini-Vixen Style Saddle Weight: 0.12 kg / 0.26 lbs Designed for William Optics Cat Series Telescopes Adds a carrying han...

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$60.00 - $60.00
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$60.00

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.