To all ZWO 2" M42 filter drawer owners (ZWO-FD-M42, example
https://astronomy-imaging-camera.com...ter-drawer-m42).
The 3rd main image shows the m48 to m42 ring that screws into the drawer.
Does your drawer have some type of notch which prevents the m48 to m42 ring from screwing straight through and and hitting the actual filter?
I feel it should have some type of stopper to prevent that, and also so the threads on extensions can stop at a known point (to help with figuring out back focus).
Mine doesn't have any type of "wall" to stop the m48-m42 ring from simply screwing straight through the thread and dropping into the glass filter area.
It also means the drawer can easily rotate e.g. if there is a tight or heavy cable pulling the camera slightly off centre, the drawer could spin, affecting field rotation etc.
I hope that explains what I'm trying to ask?