Yesterday, I went down to Gainesville, Florida to pick up my new (used) scope, a C9.25 on a CGEM mount. Weather looked good, so got first light last night. Just did a quick-and-dirty polar align on CGEM and did a minimal alignment. First impressions: The scope looks good on the outside, with just some dust on the corrector as a result of buying used. The CGEM mount is a BEAST! I've never owned anything bigger than the Orion AstroView (CG-4 equivalent), so this thing is a monstrosity to me.
Unfortunately, I popped in an eyepiece (my lowest power, 25mm is 94x) and attempted to focus. I tried, it's like it just wouldn't focus sharply (even with that nice FeatherTouch dual speed focuser, which came installed). All I would get is... mushy-looking stars. Defocusing a star showed that it might have some collimation issue (check out the attachment, this is straight from the camera). Also, I was having trouble aligning the mount on two stars, as the installed telrad had no battery, and the 50mm RACI wasn't remotely aligned with the scope. Oh, and the scope wasn't fully cooled either. Plus the narrow fov is driving me nuts, I'm used to my 6"F/5 newt.
So I said fine, enough with the C9.25. I went over to my 6"F/5 newt and popped my 25mm and 2.5x PowerMate in (75x) and focused on M42. Aaaah, small stars. But they, too, were seemingly not focusing well. Upon closer inspection showed that the stars were wobbling and waving... saying "BAD SEEING" (which I found odd, as stars weren't twinkling too much at all. And yes, the scope was cooled down). Yeah, it was bad even at 75x. I dropped it down to 30x and was happy.
So, I'm hoping that the soft stars aren't a result of bad optics, or are just normal in an SCT, but were soft because of the scope not being cooled, bad seeing, and possibly off collimation. This is my first SCT, by the way.
Going back to collimation. Like I've said, this is my first SCT. How do you collimate it? How do you know if it's the primary or secondary that needs adjustment? I don't have any collimation tools like a Cheshire eyepiece, just a simple collimation cap that came with my Newtonian. Help?
Thanks in advance!