Player One M54M-M54F 17.5mm Extender

Overview

The Player One M54M-M54F 17.5mm Extender is a machined spacer with an M54×0.75 male thread on one end and an M54×0.75 female thread on the other, adding 17.5 mm to the optical path. It is a purely mechanical part with no glass and no electronics, made from aluminum 6061-T6.

Who It's For

This is a good match if you are building an M54 imaging train and need 17.5 mm of extra length to reach a target backfocus while keeping the M54 thread on both sides.

Key Features & Design

• M54 male to M54 female: M54×0.75 male on one end, M54×0.75 female on the other, so it stacks in line.
• 17.5 mm spacing: adds a fixed 17.5 mm to the optical path.
• Aluminum 6061-T6 body: light, corrosion-resistant, and dimensionally stable.
• Fully mechanical: no optical elements and no electrical connection.

Recommended Uses

Use it to add 17.5 mm of spacing within an M54 imaging train — for example between a camera, filter wheel, or off-axis guider and the rest of the train — to hit a required backfocus.

Compatibility & Accessory Notes

The extender fits standard M54×0.75 threads. Because it is a fixed-length spacer, include its 17.5 mm in your total backfocus calculation. If you are not sure how much spacing your imaging train needs, send us your camera, filter, and corrector setup and we will work out the numbers with you.

Good to Know Before You Order

• Mechanical spacer only: it carries no optical elements and passes no electronic signal.
• Fixed 17.5 mm length: the spacing it adds is set and not adjustable.
• M54 in, M54 out: it keeps the M54 thread standard on both sides rather than converting it.

Frequently Asked Questions

Is it difficult to set up?

No — it threads directly into an M54 train by hand and needs no tools or adjustment.

What is it best used for?

Adding a fixed 17.5 mm of spacing to reach a target backfocus in an M54 imaging train.

Does it contain any optics?

No. It is a bare mechanical spacer with no lenses or coatings.

How much backfocus does it add?

17.5 mm, which you should include in your spacing total.

Bottom Line

In short: a machined aluminum M54 male-to-female spacer that adds a fixed 17.5 mm to the optical path, for dialing in backfocus within an M54 imaging train.