Everything you ever needed to know about precise collimation of your Newtonian telescope optics. 80 pages Soft cover
New Perspectives on Newtonian Collimation - 5th Edition by Vic Menard is highly recommended even if you consider you already understand the basics of this process.
An excellent soft-cover hand book with terrific illustrations and detailed instructions to ensure the reader both understands the Newtonian optical collimation process and how it can best be achieved in a precise way. This handy and very practical guide encompasses years of in-depth knowledge and experience covering every thing from visual collimation, use of visual collimating tools to red laser collimators and others.
It discusses secondary mirror designs, the importance of focuser alignment, star testing and more and will better help the reader fully understand all those reflections, abberations etc that can often frustrate the beginner in particular.