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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Baader Variable Locking Extension - 12-16mm
Provides a variable extension range of 12mm to 16mm Features a locking ring to prevent unwanted rotation Standard T-2 (M42x0.75) threads for unive...
View full detailsBaader Variable Locking/Sliding T-2 Focuser
Provides variable spacing within the T-2 system Enables fine-focus adjustment for guide cameras and eyepieces M4 clamping screw and M4 locking scr...
View full detailsBaader VariLock 29 Variable Length Adapter - 20-29mm T-2
Variable Length Adjustment: 20-29mm Standard Threads: T-2 (M42x0.75mm) Male & Female Locking Mechanism: Torsion-Resistant Knurled Ring Maximum...
View full detailsBaader VariLock 46 Variable Length Adapter - 29-46mm T-2
Variable Length Adjustment: 29mm to 46mm Locking Mechanism: Knurled locking ring with hook wrench engagement Rotational Adjustment: Rotating T-2 r...
View full detailsBaader Wide T-Ring Canon EOS - T-2 & S52
Connects Canon EOS cameras to telescopes Features a wide S52 dovetail for maximum illumination Includes a removable T-2 (M42x0.75) threaded insert...
View full detailsBaader Wide T-Ring Canon R - T-2 & S52
Connects Canon R-mount mirrorless cameras to telescopes Features a removable inner T-2 (M42x0.75) thread adapter Native connection is a wide S52 d...
View full detailsBaader Wide T-Ring Nikon - T-2 & S52
Connects Nikon F-mount cameras to telescopes Features both a standard T-2 (M42) thread and a larger S52 dovetail Clear aperture: 41 mm (T-2) / 40....
View full detailsBaader Wide T-Ring Nikon Z - T-2 & S52
Connects Nikon Z-mount cameras to telescopes Features a standard T-2 (M42x0.75) internal thread Includes a larger S52 dovetail outer ring for wide...
View full detailsBaader Wide T-Ring Sony Alpha and Minolta Maxxum - T-2 and S52
Connects Sony Alpha & Minolta Maxxum cameras to telescopes Features a native S52 dovetail for a wider light path Includes a removable T-2 (M42...
View full detailsBaader Wide-T-Ring Fujifilm X with D52i to T-2 and S52
Connects Fujifilm X-mount cameras to telescopes Features an S52 dovetail connection for M48, M68 and UFC adapters Includes a removable T-2 (M42x0....
View full detailsBaader Zeiss Camera Adapter - M44(M)/T-2(M)
Connects Zeiss M44 female threads to T-2 female threads Enables use of modern cameras with classic Zeiss optics Male M44 Thread (Zeiss side) Male ...
View full detailsBaader Zero Optical Length Adapter - 2" SCT(M) Thread/M48x0.75(F)
Male Thread: 2" SCT Female Thread: M48x0.75 Design Feature: Zero Added Optical Length Primary Application: Attaching M48 accessories to 2" SCT thr...
View full detailsBaader Zero Optical Length Adapter - 2" SCT(M)-M41.5x1(F) Zoom Mark IV to Spotting Scopes
Connects Baader Hyperion Zoom Mark IV to select spotting scopes Male Thread: 2" SCT (Schmidt-Cassegrain) Female Thread: M41.5x1 Compatible Brands:...
View full detailsBaader Zero Optical Length Adapter - 2" SCT(M)-M44x1(F) Zoom Mark IV to Spotting Scopes
Connects Baader Hyperion Zoom Mark IV to M44x1 threads Male 2" SCT thread for eyepiece connection Female M44x1 thread for spotting scope connectio...
View full detailsBaader Zero Optical Length Adapter 2" SCT(M) Thread/T-2(M)
Connects T-2 (M42x0.75) male threaded accessories to 2" SCT female threads Zero optical length design preserves critical back focus spacing Ideal ...
View full detailsCelestron 1.25" Universal Barlow and T-Adapter
Three-in-one design: 2x visual Barlow, prime focus T-adapter, and tele-extended T-adapter Doubles the magnification of any 1.25" eyepiece Connects...
View full detailsCelestron 1.25" Visual Back
Adapts Schmidt-Cassegrain rear cell threads to a 1.25" opening Accepts all standard 1.25" accessories like diagonals, eyepieces, and Barlow lenses...
View full detailsCelestron 48mm T-Adapter for EdgeHD 9.25”, 11”, and 14”
Connects full-frame DSLR and astronomical cameras to EdgeHD 9.25", 11", and 14" telescopes Features a wide M48 x 0.75 thread to eliminate vignetti...
View full detailsCelestron Camera Adapter for Canon Mirrorless, RASA 8
Attaches Canon mirrorless cameras to the 8" RASA Uses the camera's bayonet mount for a secure fit Provides minimal optical obstruction Places sens...
View full detailsCelestron Camera Adapter for Sony Mirrorless, RASA 8
Adapts Sony mirrorless cameras to the Celestron 8" RASA Uses the camera's bayonet mount for a secure connection Provides minimal optical obstructi...
View full detailsCelestron M42 Spacer Kit
Includes three M42 x 0.75 spacer rings: 7.5mm, 12mm, and 30mm Achieve precise back-focus for various telescope and camera combinations Black anodi...
View full detailsCelestron SCT to 2" Adapter
Adapts standard SCT rear cell threads to accept 2" accessories Threaded connection provides a secure, flex-free optical train Brass compression ri...
View full detailsCelestron T-Adapter for SCTs
Securely attaches SLR/DSLR cameras to Schmidt-Cassegrain telescopes Enables prime focus photography for high-resolution imaging Threads directly o...
View full detailsCelestron T-Adapter, (EdgeHD 8)
Attaches DSLR cameras to 8" EdgeHD optical tubes Threads directly onto the rear cell for a secure connection Enables prime focus photography for t...
View full detailsUnderstanding 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.