The M56 × 1 → M57 × 0.75 adapter with stop ring (PrimaLuceLab, SKU: PL3600227 ) allows you to connect cameras or accessories with an M57 × 0.75 thread to the ESATTO 2" focuser or ARCO 2" rotator. The integrated stop ring allows you to precisely set the camera angle, making framing easier without changing the back-focus budget.

The most important features of the adapter

• thread conversion: input M56 × 1 (ESATTO 2" / ARCO 2") → output M57 × 0.75 (accessories)
• optical thickness 4 mm (1.5 mm adapter + 2.5 mm ring)
• the stop ring allows for repeatable camera angle adjustment
• CNC milled precision ISO 6H threads
• anodized aluminum body - durability and lightness

Set components

• adapter M56 × 1 ↔ M57 × 0.75 with stop ring

Technical parameters

• thread on the exhaust side (input): M56 × 1 (female)
• accessory side thread (output): M57 × 0.75 (male)
• optical thickness: 4 mm (1.5 mm + 2.5 mm)
• material: anodized aluminum
• compatible devices: ESATTO 2", ARCO 2"

The PL3600227 adapter allows you to maintain full control over framing with minimal back-focus gain, which will be appreciated by astrophotographers using the ESATTO 2" focuser or ARCO 2" rotator.