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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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CA$66.00 - CA$66.00
CA$66.00
CA$66.00 - CA$66.00
CA$66.00

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

WO-YE-M63F-2IN-PI
1 in stock

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

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CA$66.00 - CA$66.00
CA$66.00
CA$66.00 - CA$66.00
CA$66.00
CA$92.00 - CA$92.00
CA$92.00
CA$92.00 - CA$92.00
CA$92.00

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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CA$92.00 - CA$92.00
CA$92.00
CA$92.00 - CA$92.00
CA$92.00
William Optics M92 to M63 Adapter for William Optics FLT91
CA$121.00 - CA$121.00
CA$121.00
CA$121.00 - CA$121.00
CA$121.00

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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CA$121.00 - CA$121.00
CA$121.00
CA$121.00 - CA$121.00
CA$121.00
CA$65.00 - CA$65.00
CA$65.00
CA$65.00 - CA$65.00
CA$65.00

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

WO-TM-MFT-M48
3 in stock

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 ...

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CA$65.00 - CA$65.00
CA$65.00
CA$65.00 - CA$65.00
CA$65.00
CA$62.00 - CA$62.00
CA$62.00
CA$62.00 - CA$62.00
CA$62.00

William Optics SCT Connection for WO Diagonals - Gold

WO-D-SCT-TA

Connects M50.8 Male to M48 Female Threads Adds 13.8 mm of Optical Length Female Thread: M50.8 Male Thread: M48 Signature William Optics Gold Anodi...

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CA$62.00 - CA$62.00
CA$62.00
CA$62.00 - CA$62.00
CA$62.00
CA$190.00 - CA$190.00
CA$190.00
CA$190.00 - CA$190.00
CA$190.00

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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CA$190.00 - CA$190.00
CA$190.00
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CA$190.00
CA$149.00 - CA$149.00
CA$149.00
CA$149.00 - CA$149.00
CA$149.00

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 Nikon F Mount Camera Bodies Precise 8....

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CA$149.00 - CA$149.00
CA$149.00
CA$149.00 - CA$149.00
CA$149.00
CA$149.00 - CA$149.00
CA$149.00
CA$149.00 - CA$149.00
CA$149.00

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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CA$149.00 - CA$149.00
CA$149.00
CA$149.00 - CA$149.00
CA$149.00
CA$17.00 - CA$17.00
CA$17.00
CA$17.00 - CA$17.00
CA$17.00

ZWO Adapter - 2mm M54(M)/M48(F)

ZWO-M54M-M48F-2
17 in stock

Connects M54 Filter Wheels to M48 Cameras Adds Only 2 mm to Optical Path Maintains 55 mm Back Focus Standard Knurled Edge for Secure Grip Designed...

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CA$17.00 - CA$17.00
CA$17.00
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CA$17.00
CA$83.00 - CA$83.00
CA$83.00
CA$83.00 - CA$83.00
CA$83.00

ZWO EOS Lens Adapter for 2" EFW

ZWO-EFW2-EOS
3 in stock

Connects Canon EOS lenses to a ZWO 2" Electronic Filter Wheel M54x0.75 female thread for direct, secure attachment Enables filtered, wide-field as...

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CA$83.00 - CA$83.00
CA$83.00
CA$83.00 - CA$83.00
CA$83.00
CA$69.00 - CA$69.00
CA$69.00
CA$69.00 - CA$69.00
CA$69.00

ZWO EOS Lens Adapter for EFW

ZWO-EFW-EOS-II
3 in stock

Connects Canon EOS lenses to ZWO Electronic Filter Wheels (EFW) Engineered for ZWO cameras with 6.5mm back focus (e.g., ASI1600) Establishes the c...

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CA$69.00 - CA$69.00
CA$69.00
CA$69.00 - CA$69.00
CA$69.00
CA$25.00 - CA$25.00
CA$25.00
CA$25.00 - CA$25.00
CA$25.00

ZWO M42 Adapter for OAG

ZWO-M42-adapter
1 in stock

M42 adapter for main imaging camera Specifications

CA$25.00 - CA$25.00
CA$25.00
CA$25.00 - CA$25.00
CA$25.00
CA$25.00 - CA$25.00
CA$25.00
CA$25.00 - CA$25.00
CA$25.00

ZWO M42 Extension - 21mm

ZWO-T2-EXT-21
14 in stock

Adds exactly 21mm of spacing to an M42 optical train M42x0.75 female threads on one side, male threads on the other Machined aluminum with a black...

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CA$25.00 - CA$25.00
CA$25.00
CA$25.00 - CA$25.00
CA$25.00
CA$41.00 - CA$41.00
CA$41.00
CA$41.00 - CA$41.00
CA$41.00

ZWO M42 Plate for CAA Rotator

ZWO-CAA-PLATE-M42
5 in stock

Converts ZWO CAA Rotator to M42 T-Threads Maintains 55mm Backfocus Standard Zero-Profile Design Adds No Optical Path Length Ideal for ASI533, ASI2...

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CA$41.00 - CA$41.00
CA$41.00
CA$41.00 - CA$41.00
CA$41.00
CA$25.00 - CA$25.00
CA$25.00
CA$25.00 - CA$25.00
CA$25.00

ZWO M42-M48 Adapter - 16.5mm

ZWO-T2-M48-16.5
9 in stock

Adds a precise 16.5mm of optical path length Connects female M42 (T2) threads to male M48 threads Essential for achieving standard 55mm back focus...

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CA$25.00 - CA$25.00
CA$25.00
CA$25.00 - CA$25.00
CA$25.00
CA$35.00 - CA$35.00
CA$35.00
CA$35.00 - CA$35.00
CA$35.00

ZWO M42e to M48i Extension - 22.5mm

ZWO-M42-M48-22.5
5 in stock

Establishes precise 55mm back focus with specific ZWO camera/filter wheel combinations Provides exactly 22.5 mm of optical path length Connects M4...

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CA$35.00 - CA$35.00
CA$35.00
CA$35.00 - CA$35.00
CA$35.00
CA$32.00 - CA$32.00
CA$32.00
CA$32.00 - CA$32.00
CA$32.00

ZWO M48 Extension - 16.5mm

ZWO-M48-EXT16.5
10 in stock

Adds exactly 16.5 mm of spacing to an M48 imaging train M48x0.75 male and female threads Wide 48 mm aperture prevents vignetting with full-frame s...

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CA$32.00 - CA$32.00
CA$32.00
CA$32.00 - CA$32.00
CA$32.00
ZWO M48-M42 Adapter
CA$17.00 - CA$17.00
CA$17.00
CA$17.00 - CA$17.00
CA$17.00

ZWO M48-M42 Adapter

ZWO-M48-M42
10 in stock

Converts female M48x0.75 threads to female M42x0.75 T-threads Adds 0mm of optical path length to the imaging train Standard accessory for many ZWO...

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CA$17.00 - CA$17.00
CA$17.00
CA$17.00 - CA$17.00
CA$17.00
CA$41.00 - CA$41.00
CA$41.00
CA$41.00 - CA$41.00
CA$41.00

ZWO M54 Adapter replacing EFW

ZWO-D70-M54F
2 in stock

Replaces the ZWO EFW to achieve 55mm back focus with the OAG-L Adds only 15 mm of optical length to the imaging train Features an internal thread ...

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CA$41.00 - CA$41.00
CA$41.00
CA$41.00 - CA$41.00
CA$41.00
CA$25.00 - CA$25.00
CA$25.00
CA$25.00 - CA$25.00
CA$25.00

ZWO M54 Extension - 16.5mm

ZWO-M54-M54-16.5
4 in stock

Optical Length: 16.5mm Connection Side 1: M54x0.75 Male Thread Connection Side 2: M54x0.75 Female Thread Material: Anodized Aluminum Descriptio...

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CA$25.00 - CA$25.00
CA$25.00
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CA$25.00
CA$25.00 - CA$25.00
CA$25.00
CA$25.00 - CA$25.00
CA$25.00

ZWO M54 Extension - 21mm

ZWO-M54-M54-21
5 in stock

Adds precisely 21mm of optical path length M54x0.75 male and female threads for secure connections Prevents vignetting with full-frame sensors Mac...

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CA$25.00 - CA$25.00
CA$25.00
CA$25.00 - CA$25.00
CA$25.00
CA$22.00 - CA$22.00
CA$22.00
CA$22.00 - CA$22.00
CA$22.00

ZWO M54 Male to M42 Female Adapter

ZWO-M54M-M42F-0
9 in stock

Thread Compatibility Durable Construction Precision Engineering Lightweight Des...

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CA$22.00 - CA$22.00
CA$22.00
CA$22.00 - CA$22.00
CA$22.00
CA$35.00 - CA$35.00
CA$35.00
CA$35.00 - CA$35.00
CA$35.00

ZWO M54(M)-M48(F) Adapter - 21mm

ZWO-M54-M48-21
1 in stock

Adds exactly 21mm of optical path length Connects M54 male threads to M48 female threads Standard 2-inch filter threading on the M48 side Black an...

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CA$35.00 - CA$35.00
CA$35.00
CA$35.00 - CA$35.00
CA$35.00
CA$17.00 - CA$17.00
CA$17.00
CA$17.00 - CA$17.00
CA$17.00

ZWO M54-M48 Adapter

ZWO-M54-M48
8 in stock

Connects M54 female threads to M48 male threads Zero-profile design preserves critical back focus Converts larger M54 ports to the common M48 stan...

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CA$17.00 - CA$17.00
CA$17.00
CA$17.00 - CA$17.00
CA$17.00

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.