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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

iOptron iAFS2 - iOptron 2'' Inline Automatic Focuser
$459.00 - $459.00
$459.00
$459.00 - $459.00
$459.00

iOptron iAFS2 - iOptron 2'' Inline Automatic Focuser

IOP-FA20

Supports a maximum payload of 5kg without slippage Delivers 0.6µm focusing resolution for critical imaging Features a 51mm clear aperture for full...

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$459.00 - $459.00
$459.00
$459.00 - $459.00
$459.00
iOptron iAFS2 2'' Camera Adapter
$32.00 - $32.00
$32.00
$32.00 - $32.00
$32.00

iOptron iAFS2 2'' Camera Adapter

IOP-P-FA20-CA

Connects Cameras to 2" Telescope Focusers Provides a Secure, Rigid Mounting Platform Standard T-Thread (M42x0.75) Camera Interface Matte Black Int...

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$32.00 - $32.00
$32.00
$32.00 - $32.00
$32.00
iOptron iAFS3 - 3-inch Inline Automatic Focuser
$539.00 - $539.00
$539.00
$539.00 - $539.00
$539.00

iOptron iAFS3 - 3-inch Inline Automatic Focuser

IOP-FA30

3-inch inline auto focuser with iLock™ technology Supports heavy imaging payloads up to 6kg 68mm clear aperture minimizes vignetting Precise 0.4um...

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$539.00 - $539.00
$539.00
$539.00 - $539.00
$539.00
iOptron iAFS3 3'' Camera Adapter
$39.00 - $39.00
$39.00
$39.00 - $39.00
$39.00

iOptron iAFS3 3'' Camera Adapter

IOP-P-FA30-CA

3-inch Barrel Diameter Provides Secure Connection for Imaging Cameras Minimizes Flexure in the Optical Train Designed for Large Format Focusers ...

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$39.00 - $39.00
$39.00
$39.00 - $39.00
$39.00
iOptron Z-axis Balancing Kit
$89.00 - $89.00
$89.00
$89.00 - $89.00
$89.00

iOptron Z-axis Balancing Kit

IOP-8439
2 en stock

Counteracts heavy imaging train weight Eliminates focuser sag and tilt Improves autofocus accuracy and repeatability Reduces mechanical stress on ...

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$89.00 - $89.00
$89.00
$89.00 - $89.00
$89.00
Économisez 9% Économisez %
$115.00
$115.00 - $115.00
$115.00
$105.00
$105.00 - $105.00
$105.00

Lacerta Kit avec micro réduction ​1:10 pour porte-oculaires Crayford

LAC-MICFOC-S

Unité de micro-réduction 1:10 Compatible avec de nombreuses marques Description Dans la boîte Téléchargements Lacerta Kit avec micro rédu...

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$115.00
$115.00 - $115.00
$115.00
$105.00
$105.00 - $105.00
$105.00
Économisez 9% Économisez %
$24.20 - $24.20
$24.20
$24.20 - $24.20
$24.20

Lumicon Tube d'Extension Fileté avec Coulant 2" - 2"

LUM-LA1025
1 restant!

Tube d'extension fileté Lumicon de 2 pouces - Oculaire de 2 pouces Repoussez les fils dans les oculaires de télescope de 2 "pour une petite extens...

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$24.20 - $24.20
$24.20
$24.20 - $24.20
$24.20
$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00

Lunt Porte-Oculaire et Plaque de Support - LS80MT

LSS-BP&F/LS80MT

La plaque arrière et le porte-oculaire Crayford standard pour le LS80MT vous permettent de convertir ce télescope solaire dédié en un télescope pou...

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$375.00 - $375.00
$375.00
$375.00 - $375.00
$375.00
$85.00 - $85.00
$85.00
$85.00 - $85.00
$85.00

Lunt Mini Porte-Oculaire Hélicoïdal - 1.25"

LSS-LSMINI/1.25

Le Lunt Mini est un porte-oculaire hélicoïdal non rotatif qui fournit une connexion filetée T2 (mâle) à T2 (femelle). Le porte-oculaire a une cour...

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$85.00 - $85.00
$85.00
$85.00 - $85.00
$85.00
$269.00 - $269.00
$269.00
$269.00 - $269.00
$269.00

Lunt Solar 1.25" R&P Focuser - Dual Speed

LSS-001-148
1 en stock

1.25" Focuser Size 10:1 Dual-Speed Reduction Fine Focus 6-8 pound (2.7-3.6 kg) Load Capacity 0.5" Draw Tube Travel CNC Machined Aluminum and Brass...

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$269.00 - $269.00
$269.00
$269.00 - $269.00
$269.00
$169.00 - $169.00
$169.00
$169.00 - $169.00
$169.00

Lunt Solar 1.25" R&P Focuser - Single Speed

LSS-001-147

Replaces stock helical focusers on Lunt Solar telescopes 1.25" eyepiece and accessory holder Rack and Pinion mechanism eliminates backlash and ima...

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$169.00 - $169.00
$169.00
$169.00 - $169.00
$169.00
$3,595.00 - $3,595.00
$3,595.00
$3,595.00 - $3,595.00
$3,595.00

Rotateur de mise au point Optec Gemini

OPC-19750

Les ingénieurs d'Optec ont développé un tout nouveau concept pour combiner les fonctions de mise au point du télescope et de rotation de la caméra ...

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$3,595.00 - $3,595.00
$3,595.00
$3,595.00 - $3,595.00
$3,595.00
$1,295.00 - $1,495.00
$1,295.00 - $1,495.00
$1,295.00 - $1,495.00
$1,295.00

Optec TCF-Leo porte-oculaire à profil bas

Options available

Les ingénieurs d'Optec ont développé un porte-oculaire de 3 pouces à profil bas, mais extrêmement robuste, pour les installations de télescopes où...

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$1,295.00 - $1,495.00
$1,295.00 - $1,495.00
$1,295.00 - $1,495.00
$1,295.00
Orion Optics UK 3" down to 2" push fit with 10mm BFD
$200.29 - $200.29
$200.29
$200.29 - $200.29
$200.29

Orion Optics UK 3" down to 2" push fit with 10mm BFD

OOUK-3-DOWN-2-PUSH-10MM

3" to 2" push fit 10mm back focal distance Individually machined to order in the UK Description Specifications In the Box Warranty 3" to ...

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$200.29 - $200.29
$200.29
$200.29 - $200.29
$200.29
Orion Optics UK 50mm Angled Finder
$155.91 - $155.91
$155.91
$175.91
$175.91 - $175.91
$175.91

Orion Optics UK 50mm Angled Finder

OOUK-IDEAL-ANGLED-FINDER-UPGRADE-50MM

50mm Aperture 90-Degree Angled Viewing Design Fully Coated Optics Reticule Crosshairs for Centering Quick-Release Dovetail Mounting Shoe Spring-Lo...

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$155.91 - $155.91
$155.91
$175.91
$175.91 - $175.91
$175.91
Orion Optics UK 50mm Angled Finderscope
$155.91 - $155.91
$155.91
$175.91
$175.91 - $175.91
$175.91

Orion Optics UK 50mm Angled Finderscope

OOUK-AG12-ANGLED-FINDER-50MM-WIDE

50mm Aperture 90-Degree Angled Viewing Fully Coated Optics Crosshair Reticle for Centering Quick-Release Dovetail Shoe Description FAQ Specific...

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$155.91 - $155.91
$155.91
$175.91
$175.91 - $175.91
$175.91
Orion Optics UK 50mm Straight-Through Wide Field Finder
$141.11 - $141.11
$141.11
$161.11
$161.11 - $161.11
$161.11

Orion Optics UK 50mm Straight-Through Wide Field Finder

OOUK-AG12-STRAIGHT-FINDER-50MM-WIDE

50mm Aperture Straight-Through Optical Path Fully Coated Optics Integrated Crosshairs for Centering Quick-Release Dovetail Shoe Description FAQ...

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$141.11 - $141.11
$141.11
$161.11
$161.11 - $161.11
$161.11
Orion Optics UK 85mm fixed adaptor ring - 1 1/4" push fit with 15mm BFD
$229.89 - $229.89
$229.89
$229.89 - $229.89
$229.89

Orion Optics UK 85mm fixed adaptor ring - 1 1/4" push fit with 15mm BFD

OOUK-85MM-FIXED-ADAPTOR-RING-1

Fits 1 1/4" push fit with 15mm back focal distance For AG and ODK telescopes Individually machined to order in the UK Description Specification...

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$229.89 - $229.89
$229.89
$229.89 - $229.89
$229.89
Orion Optics UK 85mm fixed adaptor ring - 2" push fit with 15mm BFD
$222.49 - $222.49
$222.49
$222.49 - $222.49
$222.49

Orion Optics UK 85mm fixed adaptor ring - 2" push fit with 15mm BFD

OOUK-85MM-FIXED-ADAPTOR-RING-2

Fits 2" push fit with 15mm back focal distance For AG and ODK telescopes Individually machined to order in the UK Description Specifications In...

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$222.49 - $222.49
$222.49
$222.49 - $222.49
$222.49
Orion Optics UK 85mm fixed adaptor ring - 2" push fit with 35mm bfd+-4mm
$222.49 - $222.49
$222.49
$222.49 - $222.49
$222.49

Orion Optics UK 85mm fixed adaptor ring - 2" push fit with 35mm bfd+-4mm

OOUK-85MM-FIXED-ADAPTOR-RING-2-2

Fits 2" push fit with 35mm back focal distance For AG and ODK telescopes Individually machined to order in the UK Description Specifications In...

Afficher tous les détails
$222.49 - $222.49
$222.49
$222.49 - $222.49
$222.49
Orion Optics UK 85mm fixed adaptor ring - 2" push fit with 49mm bfd+-4mm
$222.49 - $222.49
$222.49
$222.49 - $222.49
$222.49

Orion Optics UK 85mm fixed adaptor ring - 2" push fit with 49mm bfd+-4mm

OOUK-85MM-FIXED-ADAPTOR-RING-2-3

Fits 2" push fit with 49mm back focal distance For AG and ODK telescopes Individually machined to order in the UK Description Specifications In...

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$222.49 - $222.49
$222.49
$222.49 - $222.49
$222.49
Orion Optics UK 85mm fixed adaptor ring - 3" push fit with 15mm BFD
$229.89 - $229.89
$229.89
$229.89 - $229.89
$229.89

Orion Optics UK 85mm fixed adaptor ring - 3" push fit with 15mm BFD

OOUK-85MM-FIXED-ADAPTOR-RING-3

Fits 3" push fit with 15mm back focal distance For AG and ODK telescopes Individually machined to order in the UK Description Specifications In...

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$229.89 - $229.89
$229.89
$229.89 - $229.89
$229.89
Orion Optics UK Adaptor Plate for 225mm Diameter Tubes & Eris 2″ Rack & Pinion Focuser
$194.54 - $194.54
$194.54
$194.54 - $194.54
$194.54

Orion Optics UK Adaptor Plate for 225mm Diameter Tubes & Eris 2″ Rack & Pinion Focuser

OOUK-ERIS-ADAPTOR-PLATE-225MM-DIAMETER

Adapts Orion Optics UK Eris 2″ focusers to 225mm diameter tubes Adds only 11mm of height at the central axis Allows for 360° focuser rotation for ...

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$194.54 - $194.54
$194.54
$194.54 - $194.54
$194.54
Orion Optics UK AG Wynne VISUAL ADP. Screw thread to focus eyepieces.
$297.29 - $297.29
$297.29
$297.29 - $297.29
$297.29

Orion Optics UK AG Wynne VISUAL ADP. Screw thread to focus eyepieces.

OOUK-AG-WYNNE-VISUAL-ADP-SCREW

Screw-thread eyepiece adaptor For visual use with the AG Wynne corrector Individually machined to order in the UK Description Specifications In...

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$297.29 - $297.29
$297.29
$297.29 - $297.29
$297.29

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.