[jps]

My telescope is an F/3.75 or F/4 200mm newtonian(specs say an F/4 200mm with a 750mm focal length). It is an optex OP 600. My accessories are a TV 3x barlow, a 2x bintel barlow, a 25mm gso plossl, and a 9mm gso plossl, a celestron ultima 12.5mm on the way. Here's the story.

I am inexperienced. Everything is fine except for bright star images. Bright star images are atrocious. Some of the objects I have enjoyed with no obvious visual imperfectons are m80, m7, m6, the lagoon nebula, the eagle nebula, the trifid nebula, tuc 47, m24, the trapezium, the moon, jupiter and mars. When I point the telescope at bright stars such as Antares, Archernar or Rigel, the stars are a little blurry with the 9mm. Add a barlow and the image is so blurry you could never split a bright double requiring that much magnification. I have looked at bright stars at about 45 degrees above the horizon. Is this high enough? I've viewed the moon at 480x with both barlows and the 9mm(it was coming in and out a bit), so the lenses are fine.

I have addressed this on Cloudy Nights and have made inroads into my understing but still blurry bright stars so far. Even though I believe at the moment my collimation is imperfect, coma is only toward the very edge of view(remenber it's a F/3.75) and visually I find it not much of an issue compared to this blurry star business. I'm told it's unlikely that collimation would cause these blurry stars and only very limited coma. I'm also told that gross diagonal alignment might cause this problem. My mirror is not spherical. I intended to included a photo of the focusser view. The file is too large to include. A sketch was also too large. Any thoughts about whether I've got a fixable problem here and how to fix it?

Back to collimation. I've been told that the bintel laser collimator I bought is wrong for my telescope and that I need a sight tube/cheshire combination tool. If I was convinced this would fix my blurry star issue it would be purchsed immediately. I'm not convinced. I'm thinking it would only effect the edge of field coma. The other thing is I'm not sure if I can manage a star test. I can't find any diffraction rings. At what minimum power and brightnesss can this test be done? Any feedback greatly appreciated.