This continues until the dot remains in the same point regardless of the rotation of the collimator. In preparation, the main mirror should be marked giving the exact center of the mirror. Common means of marking are a permanent marker, or a adhesive paper ring. Insert the collimator into the eyepiece and turn it on. Carefully look down the front of the tube.
Lasers can be dangerous, especially when at the prime focus of a telescope mirror.
The beam should strike the secondary and then the main mirror. Adjust the secondary mirror collimation bolts until the beam strikes the center of the primary. Then adjust the primary mirror collimation bolts until the beam returns to the front of the laser, which is visible in the telescope mirror. This section assumes that the telescope is already reasonably collimated. After the laser collimation is complete, a visual inspection of the collimation should be made to ensure that all components are in the right place.