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JayKSC
scholastic sledgehammer
Reged: 01/01/05
Posts: 984
Loc: Florida
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I used and owned 5-inch and (several) 8-inch cassegrains from Meade and Celestron. While they were always good overall performers, good refractors to include achromats always seemed to be sharper and easier to focus. With the cassegrains, I always found myself tweaking the focus knob where as the refractors I've owned have always given a sudden "snap" focus. This said, I've read great things about the C9.25 and have deeply considered picking one up, especially given Ed Ting's old review.
As others have mentioned, the two scopes are more different than alike. I'd think that the 5-inch apo is more all-purpose due to it being able to provide a wider field view, good for extended objects. With the cassegrain, you'll be able to do well on most targets, but extended nebulae and clusters might not show as well.
- Jay
South Florida
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Refractor manic. 
My Sketches
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gnowellsct
professor emeritus
Reged: 06/24/09
Posts: 733
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Quote:
I used and owned 5-inch and (several) 8-inch cassegrains from Meade and Celestron. While they were always good overall performers, good refractors to include achromats always seemed to be sharper and easier to focus. With the cassegrains, I always found myself tweaking the focus knob where as the refractors I've owned have always given a sudden "snap" focus.
- Jay
South Florida
The snap to focus thing occurs because the SCTs have intrinsically higher magnifications. At higher magnifications refractor and Newtonian owners both hustle to get dual speed focusers precisely for the reason that exact focus is hard to dial in as magnification increases. The focus zone of the SCT is actually pretty large and so you're fine without the dual speed. Disclaimer: I have a dual speed feathertouch on my C14 because I thought it was somehow a clever thing to do, but in reality it's worthless.
Anyhow the fine focus on my refractors is very important (or alternatively large knobs for extra fine control).
To me snap to focus is another way of saying you like low power views. Which is a GREAT reason to prefer a refractor to an SCT. But once one accepts the SCT's higher magnifications and smaller fields, they are also very handy scopes. As I posted earlier, I'm agnostic between an FS128 and a 9.25, they both are very great instruments.
Greg N
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"Aperture will get you through times of no money better than money will get you through times of no aperture."
featuring selected astrojunk:
bunch o' widefield eyepieces
bunch o' narrowfield eyepieces
couple o' Barlows
couple o' scopes
couple o' mounts
couple o' tripods
and a pier 'n' stuff
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