What is the ZWO T2-1.25" Holder primarily used for?
The ZWO T2-1.25" Holder is used to connect any 1.25" accessory, such as an eyepiece, a small guide camera like the ASI120MM Mini, or a Barlow lens, to a component that has female T2 (M42x0.75) threads, like a filter wheel or an off-axis guider.
Will the ZWO T2-1.25" Holder scratch my eyepieces or camera nosepieces?
No. The key feature of this holder is its brass compression ring. Unlike basic adapters that use a set screw to dig into the barrel, the compression ring provides a firm, even grip around the entire barrel without marring its surface.
How do I use the ZWO T2-1.25" Holder to connect my ASI120MM camera to a ZWO filter wheel?
You would thread the T2 male side of this holder into the T2 female port on the camera-side of your ZWO filter wheel. Then, you can slide the 1.25" nosepiece of your ASI120MM camera into the holder and tighten the thumbscrew to secure it for use as a guide camera.
Can I use the ZWO T2-1.25" Holder to put a 1.25" Barlow lens in my imaging train?
Yes, this is a common application. For example, you could thread this holder onto your camera's T2 nosepiece, insert a 1.25" Barlow lens into the holder, and then insert the entire assembly into your telescope's focuser to increase magnification for planetary imaging.
What are T2 threads?
T2 threads, also known as M42x0.75 threads, are a de facto standard in astrophotography for connecting cameras, filter wheels, off-axis guiders, and other accessories. They have a diameter of 42 mm and a thread pitch of 0.75 mm.
Does the ZWO T2-1.25" Holder add to my back focus distance?
Yes, like any adapter, it adds to the optical path length. While the body itself is low-profile, you must account for its length plus the insertion depth of your 1.25" accessory when calculating your total back focus, especially if you are using a reducer or flattener with critical spacing requirements.
