It took me awhile to accept that Paul H was right about the TAK Collimation Scope (that RC collimation is much easier with one than without), especially since people like Stephen Kirk with his three part Utube video make it look so straight forward without the TAK.
Sure you can get pretty close using a Howie Glatter laser, and a Cheshire EP, and maybe finish it off with a star test adjustment, but the TAK Scope makes it less work in my opinion (now).
So what is a TAK Collimation Scope and how is it used? I have attached a few photos to demonstrate the scope and how it is used.
If you buy or borrow a TAK Collimation Scope make sure you get the 2" adaptor rings required to convert it for RC use. I got all of mine at the same time from Teleskop-Express.
It works by sliding the tube to achieve different focus perspectives inside the RC. The TAK scope has a black centre spot that should be aligned perfectly within the reflection of the Secondary Mirror centre spot, which is in turn perfectly aligned within the secondary mirror baffle reflection.
In my case the RC was very close to perfect when I received my TAK Scope so only a minor tweak on a secondary screw was required. I hope the photos explain, and I have included some close-ups of the TAK Scope instruction booklet that comes with the device (yeah instructions).
Just so long as you can see the little diffraction rings in the Tak scope dot in the centre you will be at near perfect collimation. So not only do you have to have the outer rings concentric but those tiny little rings; those are very thin and very small, those have to be found and concentric too. If you have them, then you are truly collimated.
