Product Overview

Ultra-thin precision thread conversion ring designed for astronomical and photographic optical equipment. It converts standard T2 M42×0.75mm female thread to M42×1mm male thread, solving the incompatibility issue between two common M42 thread standards. Compact lightweight aluminum construction keeps extra optical path length to a minimum, ensuring accurate back focus for sharp planetary, lunar and deep-sky astrophotography without vignetting or focal shift.

CNC machined with smooth uniform threads and matte black anti-reflection anodizing to suppress stray light inside the optical train. The large 39mm clear inner aperture fully preserves light throughput, ideal for connecting microscope objectives, camera lenses, filter wheels and telescope photographic accessories with mismatched M42 thread pitches.

Specifications

• Inner Thread: M42×0.75mm female (standard T2 astronomical thread), 4mm thread depth
• Outer Thread: M42×1mm male, 4mm thread depth
• Flange Distance: 5mm
• Total Thickness: 9mm
• Clear Inner Bore Diameter: 39mm
• Material: Solid aluminum alloy
• Surface Finish: Black anti-reflection anodized oxidation
• Color: Black
• Overall Dimension: 44 × 44 × 9mm
• Net Weight: Only 3g, ultra-lightweight with minimal focuser load

Core Features

• Cross-pitch M42 thread adapter: bridges T2 M42×0.75 astronomy gear and M42×1 camera/lens equipment
• Large 39mm clear aperture eliminates light blockage, maintains full light transmission for bright high-detail imaging
• Ultra-thin 9mm total thickness adds minimal optical path length, protects critical back focus distance for astro cameras
• Precision CNC cut smooth threads for tight wobble-free connection, guarantees perfect coaxial alignment
• Full matte black internal & external finish reduces stray light, eliminates flare and ghosting in long-exposure shots
• Micro lightweight 3g aluminum build, no extra weight burden on telescope focuser during long exposure shooting
• Wide compatibility with telescope T2 accessories, microscope objectives, vintage M42 camera lenses, filter holders

Applications

• Convert T2 M42×0.75 telescope Barlow, photo sleeves, filter wheels to M42×1mm lens/camera gear
• Adapt M42×1mm vintage camera lenses to T2 astronomical imaging systems for planetary photography
• Microscope objective conversion between RMS/M42 optical systems and standard T2 astro camera adapters
• Connect different brand optical accessories with conflicting M42 thread pitches for seamless photography

Package Includes

• 1 × M42x0.75 Female to M42x1 Male Thread Adapter Ring
• 1 × Plastic storage case for dust-proof protection

Notes

• This is a mechanical thread adapter with no optical glass; it only changes thread pitch and does not adjust focus.
• Screw threads gently by hand, avoid over-tightening to prevent thread deformation or surface scratches.
• Keep threads clean and free of dust to maintain smooth rotation and tight light-tight connection.
• Store in the included plastic case when not in use to avoid oxidation and thread contamination.