Takahashi M55.9 Extension Tube L30

Product Overview

The M55.9 Extension Tube L30 threads directly into the M55.9 x 0.75 accessory system shared across several Takahashi refractors. It carries no optics of its own — its whole job is moving a downstream accessory 30 mm further from the focuser, in one fixed step.

Who It's For

This is a good match if you're assembling a visual or imaging train on a Takahashi scope with an M55.9 x 0.75 drawtube thread and you need to add spacing without introducing a second reducer or flattener.

Key Features & Design

• M55.9 x 0.75 thread: matches the drawtube thread used on several Takahashi refractor accessory chains.
• 30 mm light path: among the longer single spacers Takahashi offers on this thread, useful when a shorter ring won't close the gap to a flattener's backfocus target.
• Solid metal construction: a single-piece spacer with no moving parts and nothing to align.

Recommended Uses

Use it to fine-tune spacing in an M55.9 visual or camera train — reaching a flattener's specified backfocus, for example, or adding clearance for a filter wheel or off-axis guider that would otherwise sit too close to the focuser.

Compatibility and Accessory Notes

It threads into any Takahashi accessory using the M55.9 x 0.75 standard. The published 30 mm is what it adds to your optical train, not its physical length measured end to end with calipers — the two numbers differ because of how far the threads seat into the mating parts on each side. The Takahashi Back Focus Guide tabulates this figure alongside the back focus target for every Takahashi telescope, so you can work out whether you need it before you order.

Frequently Asked Questions

Is it difficult to set up?

No — it threads directly into the M55.9 accessory chain with no adjustment to make.

What is it best used for?

Adding a fixed 30 mm of spacing to an M55.9 visual or imaging train.

Does it work for both visual and imaging setups?

Yes — it's a mechanical spacer with no optical element, so it works the same way in either train.

Bottom Line

An M55.9 x 0.75 spacer that adds 30 mm to your optical train. If you're not sure whether this is the spacing figure you need, send us your current train and telescope model and we'll work it out with you.