Contrepoids

Balancing a Mount Properly

Good balance is not simply equal weight. Where the counterweight sits on the shaft changes the moment of inertia, which affects how the mount responds to guiding corrections.

• Shaft diameter matching: Counterweight bores are mount-specific. A weight that nearly fits will either not seat or will mark the shaft, so the model matters more than the mass.
• Weight position: A heavier weight close to the mount gives lower inertia than a light weight far out. Lower inertia generally responds better to guiding corrections.
• Extension bars: Lengthen the shaft so a short heavy tube can be balanced with less total weight, reducing the load on the mount's bearings.
• Declination balance: Balance in both axes, not just right ascension. Declination imbalance shows up as one-directional guiding error that is easily mistaken for backlash.
• Slight east-heavy bias: A small deliberate imbalance keeps the gear teeth loaded on one face, which removes backlash effects in right ascension for many mounts.
• Cable and accessory weight: A camera, filter wheel and cable bundle shift the balance point measurably, and balance should be set with everything attached.

Why Choose David Astro for Counterweights

A counterweight is a simple product with a mount-specific fit and a real effect on guiding.

• Shaft diameter confirmed: We identify the correct bore for your mount rather than asking you to measure a shaft in the dark.
• Balance technique advice: We explain how to balance in both axes with the full imaging train attached, including the deliberate east-heavy bias where it helps.
• Extension bar sizing: For short heavy tubes we recommend an extension rather than more mass, which is easier on the mount and on you.
• Authorized dealer: Genuine weights with manufacturer warranty, in Canadian stock.
• Domestic shipping: Heavy items ship from Canada with no duties or brokerage fees for Canadian buyers.

Counterweights in Canada — Frequently Asked Questions

How much counterweight do I need?

Enough to balance with the weight roughly two thirds along the shaft, not at the far end. Sitting at the extreme end means you have too little mass and no adjustment range left.

Does counterweight position affect guiding?

Yes. A heavy weight close in gives lower rotational inertia than a light one far out, and lower inertia generally responds more crisply to guiding corrections.

Should I balance perfectly?

In declination, yes. In right ascension, many mounts guide better with a small east-heavy bias, which keeps the worm loaded against one gear face and removes backlash from the correction path.

Will any counterweight fit my mount?

No. Bore diameters vary between manufacturers and models. Tell us your mount and we will confirm the correct shaft size before shipping.

Balancing your rig?

Tell us your mount and payload and we will specify the weight and any extension. Held in Canada, shipped fast.