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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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Original price CA$271.00 - Original price CA$271.00
Original price
CA$271.00
CA$271.00 - CA$271.00
Current price CA$271.00

Baader Planetarium IMP85 Adapter S120a to M68i

BAA-2451315

Connects the IMP85 Instrument Selector's S120a port to M68i accessories Enables secure, stable mounting of M68-threaded components Essential part ...

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Original price CA$271.00 - Original price CA$271.00
Original price
CA$271.00
CA$271.00 - CA$271.00
Current price CA$271.00
Original price CA$270.00 - Original price CA$270.00
Original price
CA$270.00
CA$270.00 - CA$270.00
Current price CA$270.00

Baader Planetarium IMP85 Adapter S120a to PlaneWave SecureFit

BAA-2451317

Connects IMP85 Instrument Selector to PlaneWave SecureFit focusers Enables automated switching between three optical paths Designed for remote obs...

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Original price CA$270.00 - Original price CA$270.00
Original price
CA$270.00
CA$270.00 - CA$270.00
Current price CA$270.00
Original price CA$842.00 - Original price CA$842.00
Original price
CA$842.00
CA$842.00 - CA$842.00
Current price CA$842.00

Baader Planetarium IMP85 Extension 37 mm – for IR90 Focuser and Telescope

BAA-2451320

Provides 37 mm of fixed extension Designed for the IMP85 Instrument Port Selector Compatible with the IR90 Focuser Enables parfocal alignment of m...

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Original price CA$842.00 - Original price CA$842.00
Original price
CA$842.00
CA$842.00 - CA$842.00
Current price CA$842.00
Original price CA$11,575.00 - Original price CA$11,575.00
Original price
CA$11,575.00
CA$11,575.00 - CA$11,575.00
Current price CA$11,575.00

Baader Planetarium IMP85 – Instrument Multi Port

BAA-2451300

Enables use of up to three instruments on a single telescope Unmirrored, straight-through main optical path (Port 1) Two electronically-switched s...

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Original price CA$11,575.00 - Original price CA$11,575.00
Original price
CA$11,575.00
CA$11,575.00 - CA$11,575.00
Current price CA$11,575.00
Original price CA$37.00 - Original price CA$37.00
Original price
CA$37.00
CA$37.00 - CA$37.00
Current price CA$37.00

Baader Planetarium Inverter ring M48a (female to male)

BAA-2958555

Converts M48 Female (Internal) Threads to Male (External) Standard M48 x 0.75 Filter Thread Pitch Solves Incompatible Gender Connections in an Opt...

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Original price CA$37.00 - Original price CA$37.00
Original price
CA$37.00
CA$37.00 - CA$37.00
Current price CA$37.00
Original price CA$35.00 - Original price CA$35.00
Original price
CA$35.00
CA$35.00 - CA$35.00
Current price CA$35.00

Baader Planetarium Locking Ring T-2i – 4mm

BAA-2408190A

Provides 4mm of fixed spacing Internal T-2 (female) threads Locks rotational orientation of accessories Thin profile for fine back-focus adjustmen...

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Original price CA$35.00 - Original price CA$35.00
Original price
CA$35.00
CA$35.00 - CA$35.00
Current price CA$35.00
Original price CA$30.00 - Original price CA$30.00
Original price
CA$30.00
CA$30.00 - CA$30.00
Current price CA$30.00

Baader Planetarium M36.5 Extension tube for Alan Gee II – 19mm

BAA-2454411

19mm Extension Length Proprietary M36.5 Threading Designed for the Baader Alan Gee II Telecompressor Thin-Walled for SCT Baffle Tube Clearance ...

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Original price CA$30.00 - Original price CA$30.00
Original price
CA$30.00
CA$30.00 - CA$30.00
Current price CA$30.00
Original price CA$35.00 - Original price CA$35.00
Original price
CA$35.00
CA$35.00 - CA$35.00
Current price CA$35.00

Baader Planetarium M48 Extension Tube – 7.5 mm

BAA-2958607
2 in stock

Adds 7.5 mm of optical path length Standard M48 x 0.75 female and male threads Precision-machined for a rigid, tilt-free connection Matte black in...

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Original price CA$35.00 - Original price CA$35.00
Original price
CA$35.00
CA$35.00 - CA$35.00
Current price CA$35.00
Original price CA$185.00 - Original price CA$185.00
Original price
CA$185.00
CA$185.00 - CA$185.00
Current price CA$185.00

Baader Planetarium M48 Heavy-Duty Quick Change System

BAA-2958593
1 in stock

Enables rapid swapping of M48-threaded accessories Heavy-duty design securely holds cameras and filter wheels Rotation-proof dovetail connection p...

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Original price CA$185.00 - Original price CA$185.00
Original price
CA$185.00
CA$185.00 - CA$185.00
Current price CA$185.00
Original price CA$284.00 - Original price CA$284.00
Original price
CA$284.00
CA$284.00 - CA$284.00
Current price CA$284.00

Baader Planetarium M48-Tilter (0 - 1° image correction)

BAA-2958655

Provides 0 to 1° of tilt adjustment Corrects sensor-to-focal-plane alignment Standard M48 x 0.75 female and male threads Minimizes corner star elo...

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Original price CA$284.00 - Original price CA$284.00
Original price
CA$284.00
CA$284.00 - CA$284.00
Current price CA$284.00
Original price CA$76.00 - Original price CA$76.00
Original price
CA$76.00
CA$76.00 - CA$76.00
Current price CA$76.00

Baader Planetarium M48a Change Ring with S48a ring dovetail

BAA-2958595

Converts M48 threads to the Baader S48a dovetail standard Enables rapid, secure attachment and detachment of accessories Provides a rigid, non-rot...

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Original price CA$76.00 - Original price CA$76.00
Original price
CA$76.00
CA$76.00 - CA$76.00
Current price CA$76.00
Original price CA$132.00 - Original price CA$132.00
Original price
CA$132.00
CA$132.00 - CA$132.00
Current price CA$132.00

Baader Planetarium M48i Heavy-Duty Quick Changer with S48i Dovetail receptor

BAA-2958590

Heavy-Duty Quick-Change System M48i Thread Connection S48i Dovetail Receptor Rotation-Proof Mounting for Heavy Accessories Description FAQ Spec...

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Original price CA$132.00 - Original price CA$132.00
Original price
CA$132.00
CA$132.00 - CA$132.00
Current price CA$132.00
Original price CA$50.00 - Original price CA$50.00
Original price
CA$50.00
CA$50.00 - CA$50.00
Current price CA$50.00

Baader Planetarium M54 Extension Tube – 10 mm

BAA-2958710
1 in stock

Adds a fixed 10 mm of optical path length M54 female (M54x0.75) and male (M54x0.75) threads Prevents vignetting with larger imaging sensors Machin...

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Original price CA$50.00 - Original price CA$50.00
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CA$50.00
CA$50.00 - CA$50.00
Current price CA$50.00
Original price CA$51.00 - Original price CA$51.00
Original price
CA$51.00
CA$51.00 - CA$51.00
Current price CA$51.00

Baader Planetarium M54 Extension Tube – 15 mm

BAA-2958715
2 in stock

Adds a precise 15 mm of optical path length Standard M54 (M54x0.75) threads for modern imaging trains Machined from metal for rigidity and stabili...

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Original price CA$51.00 - Original price CA$51.00
Original price
CA$51.00
CA$51.00 - CA$51.00
Current price CA$51.00
Original price CA$54.00 - Original price CA$54.00
Original price
CA$54.00
CA$54.00 - CA$54.00
Current price CA$54.00

Baader Planetarium M54 Extension Tube – 30 mm

BAA-2958730

Adds 30 mm of Fixed Extension M54 Female and Male Threads Essential for Correcting Back Focus Matte Black Interior Minimizes Reflections Rigid, Si...

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Original price CA$54.00 - Original price CA$54.00
Original price
CA$54.00
CA$54.00 - CA$54.00
Current price CA$54.00
Original price CA$57.00 - Original price CA$57.00
Original price
CA$57.00
CA$57.00 - CA$57.00
Current price CA$57.00

Baader Planetarium M54 Extension Tube – 40 mm

BAA-2958740
1 in stock

Provides 40mm of fixed extension Standard M54 x 0.75 threads Male and female threads for easy integration Rigid design prevents flexure in the ima...

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Original price CA$57.00 - Original price CA$57.00
Original price
CA$57.00
CA$57.00 - CA$57.00
Current price CA$57.00
Original price CA$47.00 - Original price CA$47.00
Original price
CA$47.00
CA$47.00 - CA$47.00
Current price CA$47.00

Baader Planetarium M54 Extension Tube – 5 mm

BAA-2958705
1 in stock

5 mm Fixed Extension: Adds a precise, non-flexing 5 mm of optical path length to your imaging train. M54 Thread Standard: Connects seamlessly wi...

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Original price CA$47.00 - Original price CA$47.00
Original price
CA$47.00
CA$47.00 - CA$47.00
Current price CA$47.00
Original price CA$49.00 - Original price CA$49.00
Original price
CA$49.00
CA$49.00 - CA$49.00
Current price CA$49.00

Baader Planetarium M54 Extension Tube – 7.5 mm

BAA-2958707
2 in stock

Provides 7.5 mm of Fixed Extension M54 x 0.75 Male and Female Threads Essential for Correcting Back Focus Matte Black Interior to Reduce Reflectio...

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Original price CA$49.00 - Original price CA$49.00
Original price
CA$49.00
CA$49.00 - CA$49.00
Current price CA$49.00
Original price CA$11.00 - Original price CA$31.00
Original price
CA$11.00 - CA$31.00
CA$11.00 - CA$31.00
Current price CA$11.00

Baader Planetarium M54 Fine-Adjustment Rings - Aluminium

Options available

Precision M54 x 0.75 fine-adjustment spacer rings Available as a 3-ring set (0.3 / 0.5 / 1mm) or as single 0.3mm, 0.5mm or 1mm rings Provides fine...

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Original price CA$11.00 - Original price CA$31.00
Original price
CA$11.00 - CA$31.00
CA$11.00 - CA$31.00
Current price CA$11.00
Original price CA$222.00 - Original price CA$222.00
Original price
CA$222.00
CA$222.00 - CA$222.00
Current price CA$222.00

Baader Planetarium M54 Heavy-Duty Quick Change System – Changer and change ring

BAA-2958766

Enables rapid changes of heavy cameras and accessories Rotation-proof dovetail connection maintains alignment Adds only 15mm of optical length to ...

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Original price CA$222.00 - Original price CA$222.00
Original price
CA$222.00
CA$222.00 - CA$222.00
Current price CA$222.00
Original price CA$314.00 - Original price CA$314.00
Original price
CA$314.00
CA$314.00 - CA$314.00
Current price CA$314.00

Baader Planetarium M54-Tilter (0 - 1° image correction)

BAA-2958755

0 - 1° Tilt Adjustment Range M54 Female and Male Threads Corrects Sensor Tilt and Field Curvature Improves Corner Star Sharpness Rigid Connection ...

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Original price CA$314.00 - Original price CA$314.00
Original price
CA$314.00
CA$314.00 - CA$314.00
Current price CA$314.00
Original price CA$95.00 - Original price CA$95.00
Original price
CA$95.00
CA$95.00 - CA$95.00
Current price CA$95.00

Baader Planetarium M54a Change Ring with S54a ring dovetail

BAA-2958765

Adds a secure quick-release connection to any M54 thread M54a female-threaded ring for telescope side S54a male dovetail ring for camera side Cons...

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Original price CA$95.00 - Original price CA$95.00
Original price
CA$95.00
CA$95.00 - CA$95.00
Current price CA$95.00
Original price CA$153.00 - Original price CA$153.00
Original price
CA$153.00
CA$153.00 - CA$153.00
Current price CA$153.00

Baader Planetarium M54i Heavy-Duty Quick Changer with S54i Dovetail receptor

BAA-2958760

Securely mounts and rotates heavy cameras and accessories M54i female thread for telescope-side connection S54i dovetail receptor for a rigid, rot...

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Original price CA$153.00 - Original price CA$153.00
Original price
CA$153.00
CA$153.00 - CA$153.00
Current price CA$153.00
Original price CA$47.00 - Original price CA$47.00
Original price
CA$47.00
CA$47.00 - CA$47.00
Current price CA$47.00

Baader Planetarium M54i Inverter Ring (Male to Female)

BAA-2958752
1 in stock

Converts M54 Male Thread to M54 Female Thread Enables Connection of Two Male-Threaded Components Maintains a Rigid, Secure Connection in an Optica...

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Original price CA$47.00 - Original price CA$47.00
Original price
CA$47.00
CA$47.00 - CA$47.00
Current price CA$47.00

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.