How does the PrimaLuceLab OnAxisLock2 prevent my 1.25" accessories from getting scratched?
Instead of a metal set screw digging into your accessory's barrel, the OnAxisLock2 uses a double compression ring system. When you twist the outer ring, these internal rings apply even, 360-degree pressure around the barrel. This distributes the clamping force, holds the accessory securely without damaging the surface, and prevents the scratches and dents common with thumbscrew designs.
Will the OnAxisLock2 work with a focuser that isn't from PrimaLuceLab?
Yes. This OnAxisLock2 holder is designed as a universal reducer. It fits any standard 50.8mm (2-inch) connection, including the most common focusers on the market and focusers not made by PrimaLuceLab.
I'm imaging with a camera that needs precise back focus. How does the 19mm optical thickness of the OnAxisLock2 affect my setup?
The 19mm optical thickness is a fixed value that you must subtract from your available back focus. For example, if your flattener requires 55mm of back focus and you use this holder, you will have 36mm of remaining distance for other adapters and your camera sensor. Knowing this precise 19mm value is critical for achieving a flat field and sharp stars across your image.
Can I use the OnAxisLock2 with a heavy 1.25" eyepiece or a diagonal with a planetary camera attached?
Yes. The double compression ring grips the barrel with uniform 360° pressure and holds the accessory against tilting, so 31.8mm eyepieces, mirror diagonals and cameras connect without wobble and stay centered on the optical axis.
What's the difference between this OnAxisLock2 reducer and other OnAxisLock2 models?
This model (PL8410100) is a universal 50.8mm to 31.8mm reducer that fits any standard 2" focuser. PrimaLuceLab also makes the OnAxisLock2 50.8mm visual back (PL8410015), which screws onto the M56 thread of the ESATTO 2" focuser or ARCO 2" rotator. This version is the one to choose if you need to adapt a standard 2" slip-fit connection.
Is it difficult to use the OnAxisLock2 in the dark or with gloves on?
No, it's designed for field use. The outer ring is deeply knurled, so you lock and unlock accessories with fingertip pressure and no tools, even while wearing gloves. The tactile feedback of the ring lets you confirm the lock position without looking.
