I have had issues with camera tilt. Is there a way to reduce or prevent it?
I also have had trouble with tilt. I can't say I have all the answers, but I can tell you what I have learned.
First off, I think most of my camera tilt is created by using a laser to get the initial collimation. The laser and the camera don't sit in the focuser exactly the same, and that difference results in misalignment of the camera with regard to the collimation. So I have to retouch the collimation once the camera is in place.
My Newts have adjustment set screws in the focuser base that can be used to adjust the focuser tilt (and therefore, camera tilt). I have attempted to use them with a program that gave me a real time readout of camera tilt. The problem was that constantly changing atmospheric conditions had me chasing my tail. So I got it as close as I could and quit. Since then, I have decent luck cancelling it out by adjusting the secondary mirror (collimation). Doing it that way means that the camera tilt and the collimation will both be off, but the errors cancel out (for the most part). I also find that shimming the camera extension with tape helps by taking up slop between the focuser tube and the camera extension tube. It has occurred to me to put a few spots of fingernail polish on one of the tubes to tighten things up, but haven't actually tried it.
I don't recall having as much of a problem with my SCTs as my Newts. But then, I am more particular these days (my SCTs have been gathering dust for quite some time). I don't have any ideas for SCTs other than the obvious. That is, to make all of the extensions fit snug so that there isn't any appreciable sag or slop. And do what you can about mirror flop (like crank the focuser back and forth full travel a few times to redistribute the lube between the primary mirror and the support tube).
Basically, I just do a final collimation with the camera in place and call it good.
Edited by Rickster, 23 July 2019 - 08:13 PM.