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Adapters

Almost every imaging train problem in astrophotography — soft corners, elongated stars, a camera that will not come to focus — traces back to a few millimetres of the wrong adapter. David Astro carries adapters in Canada covering M42, M48, M54, M68, SCT and Nikon and Canon bayonet standards, along with barrel adapters in 1.25" and 2", all in stock and shipping from Canada.

Adapters are the one product category where buying blind is genuinely expensive. Our team calculates back-focus and thread compatibility for customers every day, so before you assemble a stack from guesswork, send us your components and we will specify the parts.

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Wanderer Astro Universal Filter Wheel Adapter for Wanderer ETA
CA$83.00 - CA$83.00
CA$83.00
CA$83.00 - CA$83.00
CA$83.00

Wanderer Astro Universal Filter Wheel Adapter for ETA

WA-UFA-ETA

Connects Wanderer ETA Directly to a Filter Wheel Required for Imaging Trains Without an Off-Axis Guider (OAG) Compatible with ZWO, QHYCCD, ToupTek...

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CA$83.00 - CA$83.00
CA$83.00
CA$83.00 - CA$83.00
CA$83.00
CA$135.00 - CA$135.00
CA$135.00
CA$135.00 - CA$135.00
CA$135.00

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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CA$135.00 - CA$135.00
CA$135.00
CA$135.00 - CA$135.00
CA$135.00
CA$127.00 - CA$127.00
CA$127.00
CA$127.00 - CA$127.00
CA$127.00

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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CA$127.00 - CA$127.00
CA$127.00
CA$127.00 - CA$127.00
CA$127.00
CA$143.00 - CA$143.00
CA$143.00
CA$143.00 - CA$143.00
CA$143.00

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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CA$143.00 - CA$143.00
CA$143.00
CA$143.00 - CA$143.00
CA$143.00
CA$80.00 - CA$80.00
CA$80.00
CA$80.00 - CA$80.00
CA$80.00

William Optics 2"-1.25" RotoLock Visual Back Adapter

Options available

Converts 2" focusers to a 1.25" holder Innovative RotoLock self-centering mechanism Dual input: 2" push-in barrel and female M48 threads Adds 38 m...

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CA$80.00 - CA$80.00
CA$80.00
CA$80.00 - CA$80.00
CA$80.00
CA$315.00 - CA$315.00
CA$315.00
CA$315.00 - CA$315.00
CA$315.00

William Optics 3.5"-2" RotoLock Visual Back Adapter

Options available

Adapts 3.5" William Optics focusers to a 2" receiver Features the secure, self-centering RotoLock mechanism Connects via M92 x 1 male threads Adds...

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CA$315.00 - CA$315.00
CA$315.00
CA$315.00 - CA$315.00
CA$315.00
William Optics 30mm Flattener Adapter
CA$80.00 - CA$80.00
CA$80.00
CA$80.00 - CA$80.00
CA$80.00

William Optics 30mm Flattener Adapter

WO-AD-M80TOM54

30mm Optical Length Connects M80 x 0.75 to M54 x 0.75 Threads For William Optics Flat68III & Flat7A Flatteners Description FAQ Specificatio...

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CA$80.00 - CA$80.00
CA$80.00
CA$80.00 - CA$80.00
CA$80.00
William Optics 4" Extender for FLT Series
CA$94.00 - CA$94.00
CA$94.00
CA$94.00 - CA$94.00
CA$94.00

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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CA$94.00 - CA$94.00
CA$94.00
CA$94.00 - CA$94.00
CA$94.00
CA$92.00 - CA$92.00
CA$92.00
CA$92.00 - CA$92.00
CA$92.00

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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CA$92.00 - CA$92.00
CA$92.00
CA$92.00 - CA$92.00
CA$92.00
CA$54.00 - CA$54.00
CA$54.00
CA$54.00 - CA$54.00
CA$54.00

William Optics 48mm T-Mount for Canon

WO-TM-CN-EOS-M48
4 in stock

Connects M48 (2-inch) Threaded Correctors to Canon EOS Cameras Wide M48 Aperture Eliminates Vignetting on Full-Frame Sensors Adds a Precise 10.6 m...

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CA$54.00 - CA$54.00
CA$54.00
CA$54.00 - CA$54.00
CA$54.00
CA$94.00 - CA$94.00
CA$94.00
CA$94.00 - CA$94.00
CA$94.00

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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CA$94.00 - CA$94.00
CA$94.00
CA$94.00 - CA$94.00
CA$94.00
CA$76.00 - CA$76.00
CA$76.00
CA$76.00 - CA$76.00
CA$76.00

William Optics 48mm T-Mount for Fuji FX - Black

WO-TM-FJ-X-M48
1 in stock

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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CA$76.00 - CA$76.00
CA$76.00
CA$76.00 - CA$76.00
CA$76.00
CA$54.00 - CA$54.00
CA$54.00
CA$54.00 - CA$54.00
CA$54.00

William Optics 48mm T-Mount for Nikon F

WO-TM-NK-F-M48
2 in stock

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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CA$54.00 - CA$54.00
CA$54.00
CA$54.00 - CA$54.00
CA$54.00
CA$94.00 - CA$94.00
CA$94.00
CA$94.00 - CA$94.00
CA$94.00

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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CA$94.00 - CA$94.00
CA$94.00
CA$94.00 - CA$94.00
CA$94.00
CA$54.00 - CA$54.00
CA$54.00
CA$54.00 - CA$54.00
CA$54.00

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

WO-TM-PT-K-M48
1 in stock

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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CA$54.00 - CA$54.00
CA$54.00
CA$54.00 - CA$54.00
CA$54.00
CA$76.00 - CA$76.00
CA$76.00
CA$76.00 - CA$76.00
CA$76.00

William Optics 48mm T-Mount for Sony E - Black

WO-TM-SN-E-M48
3 in stock

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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CA$76.00 - CA$76.00
CA$76.00
CA$76.00 - CA$76.00
CA$76.00
William Optics 54mm Flattener Extender for GT81 WIFD
CA$94.00 - CA$94.00
CA$94.00
CA$94.00 - CA$94.00
CA$94.00

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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CA$94.00 - CA$94.00
CA$94.00
CA$94.00 - CA$94.00
CA$94.00
CA$88.00 - CA$88.00
CA$88.00
CA$88.00 - CA$88.00
CA$88.00

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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CA$88.00 - CA$88.00
CA$88.00
CA$88.00 - CA$88.00
CA$88.00
CA$88.00 - CA$88.00
CA$88.00
CA$88.00 - CA$88.00
CA$88.00

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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CA$88.00 - CA$88.00
CA$88.00
CA$88.00 - CA$88.00
CA$88.00
CA$88.00 - CA$88.00
CA$88.00
CA$88.00 - CA$88.00
CA$88.00

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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CA$88.00 - CA$88.00
CA$88.00
CA$88.00 - CA$88.00
CA$88.00
CA$83.00 - CA$83.00
CA$83.00
CA$83.00 - CA$83.00
CA$83.00

William Optics Image Plane Tilt Adjuster

WO-M-FD-RC51

Designed exclusively for the William Optics RedCat 51 astrograph Corrects image plane tilt for perfectly round stars across the frame Adds only 12...

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CA$83.00 - CA$83.00
CA$83.00
CA$83.00 - CA$83.00
CA$83.00
CA$80.00 - CA$80.00
CA$80.00
CA$80.00 - CA$80.00
CA$80.00

William Optics Longer adjusting adapter for FLAT68III, FLAT7A

WO-AD-M80-45-M48

Connects FLAT68III & FLAT7A Flatteners to M48 Imaging Trains Provides a Fixed 45mm Optical Length Input Thread: M80 x 0.75 Male Output Thread:...

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CA$80.00 - CA$80.00
CA$80.00
CA$80.00 - CA$80.00
CA$80.00
CA$21.00 - CA$21.00
CA$21.00
CA$21.00 - CA$21.00
CA$21.00

William Optics M48 Female to M42 Male Adapter

WO-YE-M48-42

Connects M48 Female Threads to M42 Male Threads Adds Only 5.3mm of Optical Path Length Standard 2" Filter Thread (M48x0.75) to T-Thread (M42x0.75)...

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CA$21.00 - CA$21.00
CA$21.00
CA$21.00 - CA$21.00
CA$21.00
CA$54.00 - CA$54.00
CA$54.00
CA$54.00 - CA$54.00
CA$54.00

William Optics M48 Push-in Nosepiece for WO 2" Diagonals & UniGuide Scope

WO-WD-DIG2A
1 in stock

Connects M48 Threaded Accessories to 2" Push-in Focusers Female M48 Threads for 2" Filter Attachment Adds a Fixed 36 mm of Optical Length Male M48...

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CA$54.00 - CA$54.00
CA$54.00
CA$54.00 - CA$54.00
CA$54.00

Understanding Thread Standards and Back-Focus

An adapter does two things at once: it changes the connection type, and it changes the distance between your corrector and your sensor. The second effect is the one that causes trouble, because most reducers and flatteners have a back-focus tolerance of about one millimetre.

  • M42 (T-thread, 0.75 mm pitch): The long-standing standard for camera adapters. Its clear aperture will vignette sensors larger than APS-C, so full-frame imaging trains should avoid it.
  • M48 (2" thread, 0.75 mm pitch): The practical choice for APS-C and full-frame sensors, with enough clear aperture to avoid mechanical vignetting.
  • M54 and M68: Larger-diameter threads used by heavier astrographs and larger-format correctors where rigidity and aperture both matter.
  • SCT 2"-24 TPI: The rear-cell thread on Schmidt-Cassegrains; requires a specific adapter to reach M42 or M48 for imaging.
  • Bayonet adapters: Canon EF and Nikon F adapters place a DSLR or mirrorless body at the correct flange distance, typically 44 mm and 46.5 mm respectively.
  • Fine-tuning spacers: 0.5 mm, 1 mm and 2 mm shims that let you land exactly on a corrector's specified spacing rather than near it.

Why Choose David Astro for Adapters

An adapter is a cheap part that determines whether an expensive telescope performs. We treat it that way.

  • Free back-focus calculation: Give us your camera, filter thickness, reducer and telescope and we will return a component list with the total spacing worked out.
  • Filter thickness accounted for: Glass in the light path shifts focus by roughly one third of its thickness, and we include that in the calculation rather than leaving you to discover it.
  • Male and female threads identified: We specify the gender and standard on both ends, which is the detail most listings omit.
  • Deep Canadian stock: Hundreds of adapters held domestically, so a missing 10 mm spacer does not cost you three weeks of clear sky.
  • Authorized dealer: Genuine manufacturer parts with full warranty, shipped from Canada without duties for Canadian buyers.

Adapters in Canada — Frequently Asked Questions

How do I calculate my back-focus?
Add your camera's sensor-to-flange distance, any filter wheel or off-axis guider, the filter's optical shift, and every spacer between the camera and the corrector. That total must match the corrector's specified figure, usually 55 mm for a standard reducer.
Should I use M42 or M48?
Use M48 for any sensor larger than APS-C. M42 has enough clear aperture for smaller sensors but will mechanically vignette a full-frame chip regardless of the optics ahead of it.
Do filters change my spacing?
Yes. A filter shifts the focal plane by about one third of its glass thickness. A 3 mm filter adds roughly 1 mm to the effective optical path, which is enough to matter at a 55 mm target.
What if I order the wrong adapter?
Contact us with your setup before ordering and we will confirm the parts. That is a faster path than exchanges, and it is a service we provide free.

Send us your imaging train

We will calculate the spacing and specify every adapter you need. Canadian stock, no guesswork.