Hello, I am new here so please bear with me. I am looking to buy a new telescope and I just need to talk to someone about some questions I have. I have read lots of info online about buying a new telescope. I still am uncertain about a few things. This is what I am looking to get. An 8" Newtonian Reflector on an euqatorial mount. Okay my question is what is the best f/# that I should get? Is 6 okay or do I need higher or lower to get sharp images? I want to do star, planet, doublestar gazing as well as deep space nebula and galaxy. I am at a place where there is very little light polution. Actually there is none. Also, how hard is it to adjust the mirrors when they are not right? Thank you for taking the time. I have read much about the focal ratio and still am a little cloudy as to the exact number. Thank you again.