Back in the dark ages (before so much light pollution
- 1980's) when I had a newt, I had the two tube clamps lined with felt and another ring clamped (bolted) around the OTA which rested against the bottom clamp. I also had the clamps adjusted so one would allow the tube to rotate without loosening (the bottom one), while the other one was tighter and locked the OTA when the toggle was clamped.
The setup meant the tube was balanced length ways when the OTA ring was against the bottom clamp, and this stopped the OTA moving lengthways (I didn't have a problem with it coming up
) and I only ever loosened the top clamp toggle to rotate the tube.
Clear as mud?
Al.