Starship Part 3
Poor collimation is the number one killer of telescope performance. Many people are intimidated by the prospect of collimating their telescopes and consequently will not attempt it. As a result many telescopes, with otherwise good optics, are left operating below their true optical capability.
A laser collimator is by far the easiest technique and tool to collimate a telescope, and a laser collimator that I built is how I collimate my telescope. The laser is placed into the focuser. The diagonal mirror now has a red dot on it. It should be exactly centered in the mirror. I have marked the center of the diagonal with a small black dot, that gives me a visual placement reference for the laser beam. This dot does not affect the performance of the diagonal mirror as this dot is centered over its shadow on the primary mirror.
Once the beam is properly centered in the secondary mirror, I look down the front of the telescope at the primary mirror. The beam needs to be perfectly centered on the primary mirror. I use a paper reinforcement ring that is accurately placed in the center of the mirror for this procedure. If the beam is not perfectly centered on the primary mirror, I then make adjustments to the secondary mirror to bring the beam into the center of the ring.
Once this has been accomplished, the beam from the primary mirror needs to converge back onto the center dot on the secondary mirror. I make the necessary adjustments to the primary mirror to bring this about. When this is accomplished the telescope is collimated.