M48 30mm Spacer Ring

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 M48 x 0.75mm aluminium alloy spacer ring provides 30mm of solid, threaded spacing to help you build out your imaging train with precision. Also available in other sizes to suit your specific setup requirements.

The M48 x 0.75mm thread is the standard thread found on most 2-inch eyepieces, filters, and imaging accessories, though the actual barrel diameter of 2 inches (50.8mm) is slightly larger than the 48mm thread itself. This means the spacer ring is broadly compatible with the wide range of 2-inch filter thread equipment on the market, including field flatteners, coma correctors, filter wheels, and camera adapters. The larger aperture compared to the M42 standard also helps reduce the risk of vignetting with bigger camera sensors. Please note that thread pitch can vary slightly between manufacturers, so we recommend checking compatibility with your specific equipment before purchasing.

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.