Colonnes d'extension

Meridian Clearance and Mount Height

A German equatorial swings its tube through a wide arc, and the lowest point of that arc must clear the tripod. Extensions solve this by moving the whole pivot upward.

• Model-specific fitment: Extensions bolt between the tripod and the mount head, and bolt patterns are specific to each mount and tripod combination.
• Height calculation: Determined by tube length behind the dovetail, tripod leg spread and the mount's declination axis position — not by tube length alone.
• Rigidity cost: Every centimetre of extension raises the centre of mass and reduces stiffness slightly, so the correct approach is the minimum height that clears.
• Polar scope access: Some extensions improve access to a polar scope that was previously at an awkward height, which is a useful secondary benefit.
• Wall thickness and material: A thick-walled steel or aluminium column adds far less flex than a thin one, and the difference is visible in settle time.
• Alternative solutions: A shorter dovetail position or a pier instead of a tripod sometimes solves the same problem without raising the centre of mass.

Why Choose David Astro for Pier Extensions

An extension that is too short does not solve the problem and one that is too tall costs stability.

• Height calculated for you: Send us your tube, dovetail position, mount and tripod and we will work out the minimum clearance required.
• Fitment confirmed: We verify the bolt pattern matches both your tripod and your mount head before shipping.
• Alternatives considered first: Sometimes repositioning the tube in its rings solves the collision without an extension, and we will say so.
• Authorized dealer: Genuine hardware with manufacturer warranty, in Canadian stock.
• Ships from Canada: No duties or brokerage fees for Canadian orders.

Pier Extensions in Canada — Frequently Asked Questions

How do I know how much height I need?

Point the mount as if crossing the meridian and measure the gap, or send us your tube length, dovetail position, mount model and tripod and we will calculate the minimum.

Does an extension reduce stability?

Slightly, since it raises the centre of mass. A well-made thick-walled extension of modest height has a small effect; a tall thin one is noticeable. Use the shortest that clears.

Is there an alternative to an extension?

Sometimes. Moving the tube forward in its rings, using a shorter dovetail, or switching to a pier can all resolve a collision. We will look at those first.

Will it fit my tripod and mount?

Bolt patterns are specific to the combination. Tell us both and we will confirm compatibility before you order.

Telescope hitting the tripod?

Send us your tube, mount and tripod and we will calculate the height needed. Domestic shipping, expert support.