Importance of Proper Collimation
I remember being told that collimation on an f10 SCT is not that important. This was from a fairly reputable dealer. From my experience nothing could be further from the truth. For the best results it needs to be absolutely perfect. There are several good articles available on the web for the collimation of an SCT, so I will not get into it now. I will only recite my experience. I recall many nites after first getting my used Classic Orange C8, mounted then on the fork mount and tripod where the views while still neat seemed a bit mushy. I could usually make out the two large bands and sometimes a third on Jupiter and I could not quite make out the Cassini division all the way around in Saturn's rings.
After reading articles on collimation, I spent several different nights under the right conditions getting the optics aligned as good as I could. It is important to note that they were only off a tiny amount and I went right to high mag techniques. It is important to do the final tweak at very high mag 600x with an in focus star and insure diffraction ring is even all the way around. I now regularly see 6 major bands plus polar regions on Jupiter, Cassini all the way around, and the Crepe ring is easy. On the best nites I have even caught glimpses of the encke division.
At some star parties, some seasoned observers were impressed with the images of M13 and the planets through my C8. I had it side by side with a Tak Mewlon 210 and there were only very subtle differences in images. I am convinced that most all SCTs out there in the ameteur community are not properly collimated, owing to the reputation they recieve. Here is a link to a great site for collimation by Thierry Legault and is the best write up I have found on the subject.
Many dealers offer used equipment. There is also an excellent souce on Astroclassifieds.com or Astromart.