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Porte-oculaires et accessoires

Focus is the difference between a sharp image and a nearly sharp one, and holding it across a Canadian night — where temperatures can drop fifteen degrees between dusk and dawn — is a mechanical problem, not a patience problem. David Astro carries focusers and focuser accessories in Canada, from Crayford and rack-and-pinion drawtubes to motor kits, rotators, compression rings and adapter flanges, in Canadian stock.

We fit focusers to telescopes routinely, including retrofits that require a specific flange or drawtube adapter. If you are replacing a stock focuser or adding motorization, tell us the telescope and we will confirm the fit.

Filtres

CA$830.00 - CA$830.00
CA$830.00
CA$830.00 - CA$830.00
CA$830.00

APM Porte-Oculaire de Luxe 3.7" ZTA

APM-37-Deluxe
1 restant!

APM 3.7" Rack and Pinion Deluxe Focuser Le nouveau porte-oculaire 3,7" est de type crémaillère et pignon, avec mise au point 1:10. Il reste rigide ...

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CA$830.00 - CA$830.00
CA$830.00
CA$830.00 - CA$830.00
CA$830.00
CA$119.00 - CA$119.00
CA$119.00
CA$119.00 - CA$119.00
CA$119.00

Askar AF Kit for FMA180 Pro

ASK-ASKAF180P
1 en stock

Enables Electronic Autofocus on the Askar FMA180 Pro Designed for Seamless Integration with ZWO EAF Broadly Compatible with Most Electronic Focuse...

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CA$119.00 - CA$119.00
CA$119.00
CA$119.00 - CA$119.00
CA$119.00
CA$122.00 - CA$122.00
CA$122.00
CA$122.00 - CA$122.00
CA$122.00

Askar SQA55 Autofocus Kit

ASK-SQA55AFKIT

Designed specifically for the Askar SQA55 Astrograph Enables autofocus with nearly all brands of electronic focusers Includes 4 MXL belts and 2 pu...

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CA$122.00 - CA$122.00
CA$122.00
CA$122.00 - CA$122.00
CA$122.00
Askar Worm-and-Gear Automatic Telescope Focuser (WAF)
CA$279.00 - CA$279.00
CA$279.00
CA$279.00 - CA$279.00
CA$279.00

Askar Worm-and-Gear Automatic Telescope Focuser (WAF)

ASK-ASKARWAF

20 kg Equivalent Load Capacity 0.0182° Minimum Resolution Step Size 1:99 Worm-Gear Stepper Motor Native ASCOM Alpaca & Indigo Support 373 g Bo...

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CA$279.00 - CA$279.00
CA$279.00
CA$279.00 - CA$279.00
CA$279.00
CA$43.00 - CA$43.00
CA$43.00
CA$43.00 - CA$43.00
CA$43.00

Baader Adaptateur Diamond Steeltrack - M48x0.75(M)

BAA-2957204

Adaptateur BDS avec filetage extérieur M48 pour connecter des pièces M48 Se monte à la place du collier standard avec la bague queue d'aronde S...

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CA$43.00 - CA$43.00
CA$43.00
CA$43.00 - CA$43.00
CA$43.00
CA$40.00 - CA$40.00
CA$40.00
CA$40.00 - CA$40.00
CA$40.00

Baader Adaptateur Diamond Steeltrack - T-2(M)

BAA-2957202

Adaptateur BDS avec filetage extérieur T-2 pour connecter des pièces T-2 Se monte à la place du collier standard avec la bague queue d'aronde S5...

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CA$40.00 - CA$40.00
CA$40.00
CA$40.00 - CA$40.00
CA$40.00
CA$57.00 - CA$57.00
CA$57.00
CA$57.00 - CA$57.00
CA$57.00

Baader Adaptateur Diamond Steeltrack -M68x0.75(M)

BAA-2957206

Adaptateur BDS avec filetage extérieur M68 pour connecter des pièces M68 Se monte à la place du collier standard avec la bague queue d'aronde S5...

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CA$57.00 - CA$57.00
CA$57.00
CA$57.00 - CA$57.00
CA$57.00
CA$503.00 - CA$503.00
CA$503.00
CA$503.00 - CA$503.00
CA$503.00

Baader Porte-Oculaire Diamond Steeltrack 2" pour Newtoniens

BAA-2957230

Mise au point BDS-NT Baader Diamond Steeltrack® 2" Améliorez pratiquement n'importe quel Newtonien, petit ou grand, avec toute la douceur, la pré...

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CA$503.00 - CA$503.00
CA$503.00
CA$503.00 - CA$503.00
CA$503.00
CA$523.00 - CA$523.00
CA$523.00
CA$523.00 - CA$523.00
CA$523.00

Baader Porte-Oculaire Diamond Steeltrack 2" pour Réfracteurs

BAA-2957210

Mise au point BDS-RT Baader Diamond Steeltrack® 2" Le porte-oculaire 2" Refractor Diamond Steeltrack de Baader Planetarium donne aux réfracteurs ...

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CA$523.00 - CA$523.00
CA$523.00
CA$523.00 - CA$523.00
CA$523.00
CA$532.00 - CA$532.00
CA$532.00
CA$532.00 - CA$532.00
CA$532.00

Baader Porte-Oculair Diamond Steeltrack 2" pour Télescopes SC/HD

BAA-2957220
4 en stock

Mise au point BDS-SC Baader Diamond Steeltrack® 2" Le porte-oculaire SC Diamond Steeltrack 2 "de Baader Planetarium offre à Schmidt-Cassegrains 3...

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CA$532.00 - CA$532.00
CA$532.00
CA$532.00 - CA$532.00
CA$532.00
CA$62.00 - CA$62.00
CA$62.00
CA$62.00 - CA$62.00
CA$62.00

Baader Base Plate pour BDS-NT Diamond Steeltrack pour Newtoniens

BAA-2957231
1 en stock

Permet le montage du Baader NT Diamond Steeltrack sur des Dobson avec des surfaces de montage plates. La fixation en queue d'aronde au porte-ocul...

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CA$62.00 - CA$62.00
CA$62.00
CA$62.00 - CA$62.00
CA$62.00
Baader Planetarium Baader 3.5" Quick Changer and Instrument Rotator for PlaneWave
CA$576.00 - CA$576.00
CA$576.00
CA$576.00 - CA$576.00
CA$576.00

Baader Planetarium 3.5" Quick Changer and Instrument Rotator for PlaneWave

BAA-1324000

Enables secure, rotation-proof mounting of heavy accessories Designed for the 3.5" Hedrick Focuser on PlaneWave CDK 14" to 24" telescopes Allows f...

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CA$576.00 - CA$576.00
CA$576.00
CA$576.00 - CA$576.00
CA$576.00
Baader Planetarium Adapter S58-short to M54a – for all BDS Diamond Steeltrack®
CA$51.00 - CA$51.00
CA$51.00
CA$51.00 - CA$51.00
CA$51.00

Baader Planetarium Adapter S58-short to M54a – for all BDS Diamond Steeltrack®

BAA-2957209

Adapts the Baader S58 drawtube thread to a female M54a thread Designed for all Baader Diamond Steeltrack® (BDS) focusers Enables direct connection...

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CA$51.00 - CA$51.00
CA$51.00
CA$51.00 - CA$51.00
CA$51.00
Baader Planetarium Adapter S58-short to M68i – for all BDS Diamond Steeltrack®
CA$79.00 - CA$79.00
CA$79.00
CA$79.00 - CA$79.00
CA$79.00

Baader Planetarium Adapter S58-short to M68i – for all BDS Diamond Steeltrack®

BAA-2957207

Adapts the Baader S58 dovetail thread to M68i Provides a secure, rigid M68i female (internal) thread connection Designed for all Baader Diamond St...

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CA$79.00 - CA$79.00
CA$79.00
CA$79.00 - CA$79.00
CA$79.00
Baader Planetarium BDS-SC Adapter S88i to M48i
CA$158.00 - CA$158.00
CA$158.00
CA$158.00 - CA$158.00
CA$158.00

Baader Planetarium BDS-SC Adapter S88i to M48i

BAA-2957297

Connects Baader Diamond Steeltrack SC (BDS-SC) focusers to M48 accessories Provides a standard female M48 (M48x0.75) accessory thread Enables a ri...

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CA$158.00 - CA$158.00
CA$158.00
CA$158.00 - CA$158.00
CA$158.00
Baader Planetarium Steeldrive II Adapter set for FeatherTouch 3.5" focusers
CA$168.00 - CA$168.00
CA$168.00
CA$168.00 - CA$168.00
CA$168.00

Baader Planetarium Steeldrive II Adapter set for FeatherTouch 3.5" focusers

BAA-2957270

Enables motorization of FeatherTouch 3.5" focusers Designed for the Baader Steeldrive II motor Provides a secure, no-slip mechanical coupling Faci...

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CA$168.00 - CA$168.00
CA$168.00
CA$168.00 - CA$168.00
CA$168.00
Baader Planetarium Steeldrive II Belt Cover – 3D-printed
CA$75.00 - CA$75.00
CA$75.00
CA$75.00 - CA$75.00
CA$75.00

Baader Planetarium Steeldrive II Belt Cover – 3D-printed

BAA-2957259

Protects Steeldrive II belt and pulleys Shields drive system from dew, dust, and debris Prevents accidental snags on cables or clothing Custom-des...

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CA$75.00 - CA$75.00
CA$75.00
CA$75.00 - CA$75.00
CA$75.00
Baader Planetarium Baader Steeldrive II Controller
CA$648.00 - CA$648.00
CA$648.00
CA$648.00 - CA$648.00
CA$648.00

Baader Planetarium Steeldrive II Controller

BAA-2957260

Standalone hand controller for Baader Steeldrive II motor units Three distinct, selectable focusing modes for any scenario Full computer control a...

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CA$648.00 - CA$648.00
CA$648.00
CA$648.00 - CA$648.00
CA$648.00
Baader Planetarium Baader Steeldrive II Motor Unit
CA$401.00 - CA$401.00
CA$401.00
CA$401.00 - CA$401.00
CA$401.00

Baader Planetarium Steeldrive II Motor Unit

BAA-2957265

High-torque stepper motor handles heavy imaging loads Timing belt drive eliminates backlash for precise autofocus Contactless homing sensor enable...

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CA$401.00 - CA$401.00
CA$401.00
CA$401.00 - CA$401.00
CA$401.00
CA$303.00 - CA$303.00
CA$303.00
CA$303.00 - CA$303.00
CA$303.00

Baader Adaptateur-RT Diamond Steeltrack - 4.2" Explore Scientific

BAA-2957285

Pour se connecter aux réfracteurs Explore Scientific avec un diamètre extérieur de 4,2" et d'autres télescopes avec un diamètre de tube intérieur...

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CA$303.00 - CA$303.00
CA$303.00
CA$303.00 - CA$303.00
CA$303.00
CA$158.00 - CA$158.00
CA$158.00
CA$158.00 - CA$158.00
CA$158.00

Baader Adaptateur RT Diamond Steeltrack - Intes Micro D66

BAA-2957296

Pour se connecter à Intes Micro avec bride D66 Convient uniquement au BDS-RT Diamond Steeltrack® pour réfracteurs

CA$158.00 - CA$158.00
CA$158.00
CA$158.00 - CA$158.00
CA$158.00
CA$172.00 - CA$172.00
CA$172.00
CA$172.00 - CA$172.00
CA$172.00

Baader Adaptateur-RT Diamond Steeltrack pour Réfracteurs - M93x1(F)

BAA-2957281

Pour connecter des réfracteurs avec des filetages intérieurs M93x1 Convient uniquement au BDS-RT Diamond Steeltrack® pour réfracteurs

CA$172.00 - CA$172.00
CA$172.00
CA$172.00 - CA$172.00
CA$172.00
CA$57.00 - CA$57.00
CA$57.00
CA$57.00 - CA$57.00
CA$57.00

Baader Adaptateur-RT Diamond Steeltrack pour Réfracteurs Sky-Watcher - M90x1(F)

BAA-2957283

Pour se connecter aux réfracteurs Skywatcher avec filetage extérieur M90x1 Convient uniquement au BDS-RT Diamond Steeltrack® pour réfracteurs C...

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CA$57.00 - CA$57.00
CA$57.00
CA$57.00 - CA$57.00
CA$57.00
CA$59.00 - CA$59.00
CA$59.00
CA$59.00 - CA$59.00
CA$59.00

Baader Adaptateur-RT Diamond Steeltrack pour Réfracteurs Sky-Watcher - M90x1.5(M)

BAA-2957284

Pour se connecter aux réfracteurs Skywatcher avec filetage extérieur M90x1,5 Convient uniquement au BDS-RT Diamond Steeltrack® pour réfracteurs

CA$59.00 - CA$59.00
CA$59.00
CA$59.00 - CA$59.00
CA$59.00

Focuser Mechanics and What Matters Under Load

A focuser has to hold a camera train weighing several kilograms perfectly square to the optical axis while moving in increments of a few microns. Two things determine whether it does: the drive mechanism and the load rating.

  • Crayford focusers: A friction roller on a flat surface, giving smooth, backlash-free travel. Excellent for visual and light imaging loads; can slip under heavy trains, particularly when pointed near zenith.
  • Rack-and-pinion focusers: Toothed engagement that will not slip regardless of load, which is why most heavy imaging trains use them. Modern designs have effectively eliminated the old backlash complaints.
  • Motorized and electronic focusers: Stepper-driven focus with position repeatability, enabling autofocus routines and temperature compensation across a session.
  • Rotators: Precise framing and camera angle control without breaking the imaging train, and essential for optimizing off-axis guide star placement.
  • Compression rings: Replace a single set screw that tilts and marks your barrel with even radial clamping — a small part with a visible effect on star shapes.
  • Adapters and flanges: Telescope-specific mounting plates that let a third-party focuser replace a stock one.

Why Choose David Astro for Focusers and Accessories

Focuser upgrades are one of the most cost-effective improvements in astrophotography, and one of the easiest to order incorrectly.

  • Retrofit fit checks: We identify the adapter flange your specific telescope needs, and confirm that the new focuser's travel and profile will still let you reach focus.
  • Load rating advice: We weigh your intended imaging train against the focuser's rated capacity, including the tilt load that shows up when the tube is near zenith.
  • Authorized dealer: Genuine parts with full manufacturer warranty, serviced in Canada.
  • Canadian stock: In-stock focusers and accessories ship domestically without duties or brokerage charges.
  • In-house repair: We service focuser mechanics and electronics directly, which matters for a component with moving parts that see heavy use.

Focusers in Canada — Frequently Asked Questions

Crayford or rack-and-pinion for imaging?
Rack-and-pinion, once your imaging train exceeds roughly 2 kg. A Crayford's friction drive can slip under load at steep angles, and the slip is often mistaken for focus drift.
Will a motorized focuser fit my existing focuser?
Often yes, through a telescope-specific bracket that couples to the fine-focus shaft. Tell us the focuser model and we will confirm whether a bracket exists or a full replacement is needed.
How much does focus shift with temperature?
Enough to matter. A metal tube contracts measurably over a 15 degree drop, and at fast focal ratios the critical focus zone is only tens of microns. Temperature-compensated autofocus solves it.
Do you carry focusers for older telescopes?
We carry a wide range of adapter flanges covering many discontinued tubes. Send us the make and drawtube diameter and we will check.

Upgrading your focuser?

Tell us your telescope and imaging train weight and we will specify the right focuser and flange. Canadian stock, expert fitting advice.