Accessoires de mise au point

Small Parts That Fix Real Focuser Problems

Each item here corresponds to a symptom. Matching the part to the symptom is quicker and cheaper than a replacement focuser.

• Compression rings: Replace a single set screw with even radial clamping. This stops the barrel marking and, more importantly, removes the tilt a point-contact screw induces in an imaging train.
• Motor brackets and couplers: Attach a stepper motor to an existing fine-focus shaft, adding absolute positioning and autofocus without replacing the drawtube.
• Reduction knobs and dual-speed retrofits: Add 10:1 fine focus to a single-speed focuser, which matters most at fast focal ratios where the critical focus zone is very narrow.
• Drawtube tension and locking hardware: Adjust or restore the friction that stops a Crayford slipping under a heavy camera train at steep angles.
• Rotation collars: Rotate the camera for framing without unthreading the imaging train and losing your spacing.
• Extension tubes and terminations: Reach focus with accessories that would otherwise fall inside the drawtube's travel range, and convert the output to standard imaging threads.

Why Choose David Astro for Focuser Accessories

Diagnosing the fault correctly is worth more than the part itself.

• Symptom-based advice: Tell us what is happening — slipping, drifting focus, marked barrels, one-sided stars — and we will tell you which part addresses it rather than selling an upgrade you may not need.
• Model-specific fitting: Motor brackets and reduction retrofits are made for particular focusers, and we confirm the match before shipping.
• Tilt awareness: We treat set-screw induced tilt as a real optical problem, because at fast focal ratios it produces star elongation that looks like a corrector spacing error.
• Authorized dealer: Genuine parts with full manufacturer warranty, in stock, with fast shipping across Canada and worldwide.
• Ships from Canada: Domestic delivery with no duties or brokerage fees for Canadian buyers.

Focuser Accessories in Canada — Frequently Asked Questions

Will a compression ring really improve my images?

If you are using a single set screw on a heavy camera train, very likely. Point contact tilts the barrel by a fraction of a degree, which at f/5 is enough to elongate stars on one side of the field.

Can I motorize any focuser?

Most focusers with an exposed fine-focus shaft can take a bracket-mounted motor. Tell us the focuser model and we will confirm whether a bracket exists or whether replacement is the better route.

Why does my focuser slip near zenith?

Crayford focusers rely on friction, and the load direction changes as the tube tilts. Adjusting drawtube tension often fixes it; if not, the train has exceeded what the mechanism can hold and a rack-and-pinion is the answer.

Do you carry parts for older focusers?

Often. Many manufacturers supply service parts to dealers that are not listed publicly. Send us the model and we will check availability.

Diagnosing a focuser problem?

Describe the symptom and we will identify the part that fixes it. Canadian stock, fast domestic shipping.