Astrodymium Rotating Tilt Adjusters for M42/M48, and M54 Threads


Size: M42
Sale price$19.99
In stock


These rotating tilt adjusters compensate for tilt in your imaging train when using any threaded adapter or extension tube. The adapter only needs to be partially unthreaded to allow the tilter to rotate to the area that needs to be compensated for.

Also available on Agena Astro (United States) and First Light Optics (UK / Europe)!

The M42 size is compatible for use with ZWO's EOS/Nikon adapters

Each tilt adjuster adds 0.40mm ± 0.03 of backfocus.

Each set comes with 3 levels of adjustment: 0.1, 0.2, and 0.3mm, and the corresponding amount is debossed onto the adjuster itself with roman numerals.

These are meant for correcting large amounts of tilt. For reference: aluminum foil is 0.016 mm thick.

  • I = 0.1mm
  • II = 0.2mm
  • III = 0.3mm

How does it work?

A raised section on each adjuster acts as a shim, which pushes one side of a threaded adapter higher than the other, this is the mechanism that creates the tilt effect.

The maximum amount of compensation that can be produced is dependent on the tolerance of the threads (how much slop they have).

For example, ZWO's extension tubes (16.5 & 21mm) have been tested to produce a maximum of 0.20mm worth of tilt.

Check out some reviews: 


Made out of PETG plastic and can handle up to 80C (176F) temperatures.

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Customer Reviews

Based on 1 review
Kayden J
Use this product instead of using your own shims

I had some tilt issues with my lens setup, and in the past I used pieces of paper as shims to try to fix the tilt but it was a very tedious process. This product does the job much better and is way easier to install.

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