Reduction ring for female thread M48 to female thread M42. This zero optical length adapter allows the attachment of M42 thread telescopes while maintaining the optical length of the entire astrophotography set, compatible with the camera's back focus.
• Zero optical length will not affect the camera's back focus
• perfect for connecting telescopes with M42 thread with intermediate rings and off-axis guides with M48 thread
• optical length: 0 mm
• male thread: M48 x 0.75
• female thread: M42 x 0.75
• reduction ring M48-M42