Use the 1mm Alpine Astronomical Baader M48 Aluminum Fine-Adjustment Ring to fine-tune your rig during eyepiece projection astrophotography techniques.
The M48 thread size fits most 2" eyepieces and accessories and is used with the large-format T-2 gear that is required to cover today's larger imaging sensors and prevent vignetting. This extremely thin spacer ring is machined out of aluminum to be strong yet durable and is made without threads for easy installation and removal. The ring also offers the added benefit of preventing binding between two threaded parts to make disassembly faster and easier without damaging your gear. The 1mm thickness equates to roughly 1 1/3 turn of rotation. Alpine offers three sizes of the spacer ring, and each is color coded for easy identification—this size is colored gold.