M42 40mm Spacer Ring
M42 x 0.75mm Aluminium Alloy Extension Spacer Ring for telescope photography. This 40mm spacer can help you achieve precise back-focus spacing in your imaging train.
Getting your back-focus distance right is essential for sharp, well-corrected astrophotography and sometimes you need more than thin shims to bridge the gap. This M42 x 0.75mm aluminium alloy spacer ring provides 40mm of solid, threaded spacing to help you build out your imaging train with precision.
The M42 x 0.75mm external thread is one of the most widely used standards in astrophotography, ensuring broad compatibility with telescopes, camera adapters, field flatteners, coma correctors, and filter wheels. Machined from aluminium alloy, the ring is lightweight yet durable, resisting wear over repeated use without adding unnecessary bulk to your setup.
Use it on its own or combine it with other spacer rings and shims to dial in your exact required spacing. Whether you're setting up a new imaging train from scratch or fine-tuning an existing configuration, this spacer ring gives you a reliable, threaded connection at the length you need.