Hello,
You can get a lot of good info (with diagrams) from the web, from cheap camera film caps to check the secondary with to full blown collimation assistance.
The good news is you really shouldn't have to worry about the secondary more than once. If you have a F6 8", they hold collimation very well and really only need tweaking between use unless bumped. Slower scopes have a larger bullseye for collimation to make life a little easier as well.
I'd view collimation as a two step format.
- Set your scope with the optic paths set as good as you can with the laser collimator.
- Look at star testing your collimation after the mirror has cooled for the nights viewing for a final fine tune.
Steve
Gary Seronik is a good source of well written info as well.
https://garyseronik.com/a-beginners-...o-collimation/