Passer au contenu
Égalisation des prix Retours sous 30 jours* Parlez à un astronome avant d'acheter

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

$79.00 - $79.00
$79.00
$79.00 - $79.00
$79.00

Daystar Tube d'Extension Quantum - 2" 80mm de long

DAY-GM2D2

Tube d'extension Daystar Quantum - 2" 80mm de long

$79.00 - $79.00
$79.00
$79.00 - $79.00
$79.00
Explore Scientific 3-inch Self-Centering Focuser
$849.99 - $849.99
$849.99
$849.99 - $849.99
$849.99

Explore Scientific 3-inch Self-Centering Focuser

ES-FOC3

3-inch self-centering draw tube 17 lb (7.7 kg) lifting capacity 9:1 dual-speed focusing system 84.5mm of precision draw tube travel Rotatable back...

Afficher tous les détails
$849.99 - $849.99
$849.99
$849.99 - $849.99
$849.99
Explore Scientific 3-inch Self-Centering Focuser with Back Cell Adapter for FCD100-127-CF
$999.99 - $999.99
$999.99
$999.99 - $999.99
$999.99

Explore Scientific 3-inch Self-Centering Focuser with Back Cell Adapter for FCD100-127-CF

ES-FOC3-BC100127

3-inch Self-Centering Focuser Design 17 lb Lifting Capacity for Heavy Imaging Trains 9:1 Dual-Speed Helical Rack-and-Pinion Mechanism 84.5mm of Pr...

Afficher tous les détails
$999.99 - $999.99
$999.99
$999.99 - $999.99
$999.99
Explore Scientific 3-inch Self-Centering Focuser with Back Cell Adapter for White Tube ED127 and FCD-100
$999.99 - $999.99
$999.99
$999.99 - $999.99
$999.99

Explore Scientific 3-inch Self-Centering Focuser with Back Cell Adapter for White Tube ED127 and FCD-100

ES-FOC3-BC100127T

Designed for Explore Scientific white-tube ED127 and FCD-100 refractors 17 lb instrument lifting capacity Self-centering compression system elimin...

Afficher tous les détails
$999.99 - $999.99
$999.99
$999.99 - $999.99
$999.99
$59.99 - $59.99
$59.99
$59.99 - $59.99
$59.99

Explore Scientific Anneaux de Chercheur 50mm - Hauteur Standard

ES-FNDRRGSSTD

Les anneaux de recherche Explore Scientific sont tous conçus pour les chercheurs de 50 mm. Choisissez parmi un support classique à profil bas (envi...

Afficher tous les détails
$59.99 - $59.99
$59.99
$59.99 - $59.99
$59.99
$89.99 - $89.99
$89.99
$89.99 - $89.99
$89.99

Explore Scientific Anneaux de Chercheur 50mm - Élevé

ES-FNDRRGSTALL

Les anneaux de chercheur Explore Scientific sont tous conçus pour les chercheurs de 50 mm. Choisissez parmi un support classique à profil bas (env...

Afficher tous les détails
$89.99 - $89.99
$89.99
$89.99 - $89.99
$89.99
$79.99 - $79.99
$79.99
$79.99 - $79.99
$79.99

Explore Scientific Anneaux de Chercheur 50mm - pour Chercheur Coudé

ES-FNDRRGSRA

Les anneaux de recherche Explore Scientific sont tous conçus pour les chercheurs de 50 mm. Choisissez parmi un support classique à profil bas (env...

Afficher tous les détails
$79.99 - $79.99
$79.99
$79.99 - $79.99
$79.99
$199.99 - $199.99
$199.99
$199.99 - $199.99
$199.99

Explore Scientific Chercheur Polaire 8x50 Illuminé - Coudé

ES-VFEI0850-RA

Avec ses marques de référence polaires nord et sud, le viseur polaire éclairé 8x50 d'Explore Scientific avec le NOUVEL illuminateur longue durée de...

Afficher tous les détails
$199.99 - $199.99
$199.99
$199.99 - $199.99
$199.99
$79.99 - $79.99
$79.99
$79.99 - $79.99
$79.99

Explore Scientific Chercheur 8x50 Non-Illuminé - Droit

ES-VF0850S

Le chercheur 8x50 a un réticule standard pour vous aider à centrer les objets avec précision. La visionneuse d'images droite et non dressée a un c...

Afficher tous les détails
$79.99 - $79.99
$79.99
$79.99 - $79.99
$79.99
$179.99 - $179.99
$179.99
$179.99 - $179.99
$179.99

Explore Scientific Chercheur 8x50 Illuminé avec Support - Droit

ES-VFEI0850-01

L'Explore Scientific 8x50 produit un large champ de vision de 6° et permet une mise au point précise de l'objectif principal et du réticule éclairé...

Afficher tous les détails
$179.99 - $179.99
$179.99
$179.99 - $179.99
$179.99
$99.99 - $99.99
$99.99
$99.99 - $99.99
$99.99

Explore Scientific Adaptateur FFFR507X-00 à Porte-Oculaire HEX 2.5"

ES-510366

Explorez l'adaptateur scientifique pour permettre l'utilisation du correcteur FFFR507X-00 3" 0,7x sur le porte-oculaire hexagonal 2,5"

$99.99 - $99.99
$99.99
$99.99 - $99.99
$99.99
$299.99 - $299.99
$299.99
$299.99 - $299.99
$299.99

Explore Scientific Porte-Oculaire à Crémaillère Série APO EDT

ES-FOCEDAPO-RP

Trouver et maintenir cette mise au point nette parfaite est presque sans effort avec le porte-oculaire à crémaillère d'Explore Scientific. Défini p...

Afficher tous les détails
$299.99 - $299.99
$299.99
$299.99 - $299.99
$299.99
$49.99 - $49.99
$49.99
$49.99 - $49.99
$49.99

Explore Scientific Base de Chercheur

ES-FNDRBASEBLK

Cette base de chercheur est spécialement conçue pour vous permettre de fixer l'un des chercheurs de haute qualité d'Explore Scientific au télescop...

Afficher tous les détails
$49.99 - $49.99
$49.99
$49.99 - $49.99
$49.99
$59.99 - $59.99
$59.99
$59.99 - $59.99
$59.99

Explore Scientific Illuminateur II pour Chercheur

ES-FNDRILLUM-02

Avez-vous déjà été frustré par l'illuminateur standard ? La batterie est-elle toujours vide lorsque vous l'allumez ? L'Illuminator II offre désorm...

Afficher tous les détails
$59.99 - $59.99
$59.99
$59.99 - $59.99
$59.99
$29.99 - $29.99
$29.99
$29.99 - $29.99
$29.99

Explore Scientific Tube d'Extension 1" pour Porte-Oculaire à Crémaillère

ES-ESRPEXT1

Tube d'extension de 2,5 cm pour porte-oculaire à pignon et crémaillère Explore Scientific

$29.99 - $29.99
$29.99
$29.99 - $29.99
$29.99
$39.99 - $39.99
$39.99
$39.99 - $39.99
$39.99

Explore Scientific Tube d'Extension 2" pour Porte-Oculaire à Crémaillère

ES-ESRPEXT2
1 en stock

Tube d'extension de 5,1 cm pour porte-oculaire à pignon et crémaillère Explore Scientific

$39.99 - $39.99
$39.99
$39.99 - $39.99
$39.99
$44.99 - $44.99
$44.99
$44.99 - $44.99
$44.99

Explore Scientific Tube d'Extension 2.5" pour Porte-Oculaire à Crémaillère

ES-ESHEXEXT2

Tube d'extension de 6,3 cm pour porte-oculaire à pignon et crémaillère Explore Scientific

$44.99 - $44.99
$44.99
$44.99 - $44.99
$44.99
Explore Scientific ReflexSight
$59.99 - $59.99
$59.99
$59.99 - $59.99
$59.99

Explore Scientific ReflexSight

ES-REFLECT-01

Zero-power reflex sight for intuitive aiming Multi-dot reticle with 4.0°, 2.0°, and 0.5° circles Fits standard mini-Vixen style dovetail bases Int...

Afficher tous les détails
$59.99 - $59.99
$59.99
$59.99 - $59.99
$59.99
$49.99 - $49.99
$49.99
$49.99 - $49.99
$49.99

Explore Scientific Base en T de Chercheur pour Série Essential

ES-FNDRBASE-ESSEN

Cette base de chercheur en forme de T est spécialement conçue pour vous permettre de fixer l'un des chercheurs de haute qualité d'Explore Scientif...

Afficher tous les détails
$49.99 - $49.99
$49.99
$49.99 - $49.99
$49.99
$90.00 - $90.00
$90.00
$90.00 - $90.00
$90.00

Howie Glatter Adaptateur de Centrage d'Oculaire Parallizer 2.0"

SI-A20-SCT-P

Présentation du SCT Parallizer®. Cette nouvelle application du principe breveté Parallizer® de Howie Glatter place la barre plus haut en termes de ...

Afficher tous les détails
$90.00 - $90.00
$90.00
$90.00 - $90.00
$90.00
$90.00 - $90.00
$90.00
$90.00 - $90.00
$90.00

Howie Glatter Adaptateur de Centrage d'Oculaire 2.0" to 1.25"

SI-EA20-205P

Mode d'emploi Il existe une idée fausse selon laquelle le problème du système d'ajustement cylindrique que nous utilisons pour les oculaires et aut...

Afficher tous les détails
$90.00 - $90.00
$90.00
$90.00 - $90.00
$90.00
iOptron Electronic Automatic Focuser - iEAF
$199.00 - $199.00
$199.00
$199.00 - $199.00
$199.00

iOptron Electronic Automatic Focuser - iEAF

IOP-8453

5 kg Maximum Payload Capacity High-Precision Stepper Motor Drive Built-in Temperature Sensor for Focus Compensation ASCOM Compatible for Automated...

Afficher tous les détails
$199.00 - $199.00
$199.00
$199.00 - $199.00
$199.00
iOptron Finder Scope 6X30mm
$52.00 - $52.00
$52.00
$52.00 - $52.00
$52.00

iOptron Finder Scope 6X30mm

IOP-6151

6x Magnification 30mm Aperture Includes Mounting Bracket Wide Field of View for Easy Star-Hopping Optical Finder Design Description FAQ Specifi...

Afficher tous les détails
$52.00 - $52.00
$52.00
$52.00 - $52.00
$52.00
iOptron Finder Scope 8x50mm
$88.00 - $88.00
$88.00
$88.00 - $88.00
$88.00

iOptron Finder Scope 8x50mm

IOP-6152

8x Magnification 50mm Aperture Wide Field of View for Locating Objects Includes Mounting Bracket Description FAQ Specifications In the Box Down...

Afficher tous les détails
$88.00 - $88.00
$88.00
$88.00 - $88.00
$88.00

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.