Expert: Paul Wagner - 7/24/2005

Question
Hi,

I may have asked you a question before, but not sure. My question involves the Celestron C 9.25" catadioptric scopes. The OTA also apparently bridges the gaps in Celestron's entire inventory - whether it be Nexstar, CGE, whatever. What I refer to is its consistently high rating by reviewers. But here's what I don't understand: it seems that ONLY the 9.25" gets these high ratings and not the 8" or the 11". Assuming the optics are the same within the Celestron line, why just this one size aperture? The 8" and 11" both get good writeups, but the 9.25" is the one that always gets outstanding reviews. IS there a difference in the optics? That doesn't seem to make good business sense. Can't you put a reducer on the 11" and have a 9.25"? One dealer said you can, and with the desired results. He also said something about a 'perfect marriage' of focal length and some other factor(s) I can't remember. It's too late for me, I just got the 11" for future deep-sky observing - I'm just insanely curious. Thank you  very much.

Tom

Answer
Dear Tom:

There SHOULDN'T be a difference in the optics.  I suspect it is a little simpler than that.  Since lots of 8 inch scopes are around, the 9.25 is just a big bigger, and  compares very well with those 8 inch scopes.  I don't think any of them can compete with the 11 inch scope--but I am a huge believer in aperture.  11 inches also means more weight, and so the scope is harder for one person to heft...but if I had my choice, it would be the 11--and that's true for most of those reviewers...too!

Paul Wagner