Step 8: (5) Stabilize the focusing system
The focusing tube moves with the help of a rack and pinion mechanism. Shake it a little with your hand up and down. If it moves then it needs stabilization.
I used two pieces of tape underneath parallel to the rack. The pinion is kept in place with a cover and two screws. This should be adjusted so that the tube does not slide.
Since I use a camera on the scope, I controlled these two screws in order to hold the camera without sliding.