This video is about adjusting the secondary mirror of your Newtonian telescope. This should not be done by a beginner until they have mastered the skills shown in part one: Newtonian Collimation for Absolute Beginners. The techniques show in this video should not be used unless your secondary mirror is very far out of alignment, perhaps due to a disastrous accident. The secondary has to be very far out of collimation for it to seriously affect the view at the eyepiece. If it’s just a little off leave it alone! Before making any adjustments shown in this video, double check to make sure you have carefully followed the instructions in the first video. It won’t take you very long to go through them again. You may save yourself a lot of additional heartache. Newtonian Collimation for Absolute Beginners: I am a retired Astronomy Professor. I do not make any money or benefit in any way from my recommendations. Unlike many Youtube reviewers, I am not an Amazon affiliate. I make nothing when you make a purchase. Links to more detailed instructions: Gary Seronik (BEST): Sky and Telescope (SUPERB): Highpoint Scientific: Small Optics: Using a collimation cap: Star Collimating Video: Here is the best Collimation Device for the beginner (Cheshire Eyepiece): Best Beginner Telescopes: How to Select a Beginner Telescope: