M54M to M42M Adapter – 1.5mm Back Focus
This precision-machined M54M to M42M adapter is designed for astrophotography imaging trains where precise back focus spacing is critical. With an ultra-thin mechanical thickness of just 1.5mm, it allows fine adjustment without exceeding reducer or flattener spacing requirements.

Ideal for converting between M54 and M42 (T-thread) components, this adapter is commonly used in advanced imaging setups involving field flatteners, focal reducers, filter wheels, off-axis guiders, and cameras.
CNC-machined to tight tolerances and finished in matte black to minimise internal reflections, it provides a clean, reliable, and professional-grade connection within complex imaging trains.
Key Features
- M54 male to M42 male (T-thread) conversion
- Ultra-thin 1.5mm back focus for precise spacing control
- CNC-machined for accuracy and durability
- Matte black finish to reduce internal reflections
- Designed for advanced astrophotography imaging trains
Specifications
- Thread A: M54 × 0.75 (Male)
- Thread B: M42 × 0.75 (Male, T-thread)
- Optical / Mechanical Length: 1.5 mm
- Material: Aluminium alloy
- Finish: Black anodised
What’s Included
- 1 × M54M to M42M Adapter (1.5mm back focus)