Celestron 9.25 vs. Classic 1970 orange 8 Celestron

Hi everyone, I am considering the purchase of the 9.25 Celestron CPC. My question is just how much more on the visual side does the 9.25 scope give me over my 8 inch Celestron. I have one of the older Celestron which gives very sharp views and I am just wondering if the larger Celestron will give me that much more. I do not want to go larger because of the weight question and I am strictly a visual observer Any thoughts would be helpful. Thanks in advance.

John

Before I got my NextStar 11, I considered a 9.25 because of the weight. Then I hefted both. For the extra aperture, I didn't really feel the difference. The 11 weighs only 7 pounds more than the 9.25. They are essentially the same size physically too.

I have found that the problem is not in carrying or managing the beast. It is bending and twisting to get it out of the suitcase style JMI case. On occasions, I have carried it to star parties or dark skies riding under a blanket, belted into the passenger seat of my car where it is much easier to grab. Once lifted, the scopes are balanced well. On more than one occasion, I have carried the 11 across several dozen yards of observing field to set up. I am careful to not trip, but my 61 year old back doesn't complain about holding or carrying - only lifting it from the blasted case. Now I believe that the new JMI cases for the CPC is a straight up lift, not the twist and groan of the old NexStar cases.

I've never regretted getting the 11. The cost is close and the weight is closer to the 9.25. And it would definitely be an improved view on the 8.

Jim in Texas

I have owned the c6, c8, c9.25, and c11. The c9.25 will give you a brighter image then the c8, but there are some other things to consider. What mount you will be using. You can still use a c8 with a lighter weight mount. But the c9.25 at 20lbs ota only, needs a much stronger mount.

Hi John,

I have a Nexstar 11, have looked though a Celstron 8" quite a few times during the period I've owned the 11", and have used a Celstron 9.25 once. It's interesting to compare the 9.25" to either the 8" or 11" because it's optically different. Although they are all f/10, the 9.25" has a slower primary mirror focal ratio and therefore a lower magnification secondary mirror. This results in a flatter field of view. My one real gripe with the 11" and (even more so the 8") is that the image quality degrades in the outer field of view with longer focal length eyepieces. This is very clear with a Pentax 20 mm XW, a TeleVue 13 mm ethos eyepiece, and a TeleVue 27 mm Panoptic. Some of the image quality degradation is due to other aspects of the telescope optical design (coma, in particular). You can determine that coma is only part of the story with those eyepieces because you can focus on a star in the other field and get a much sharper image out there while the central field degrades. My one view through a 9.25" was a number of years back, but the image quality over the full field of view impressed me.

You mention image quality as being important, so the 9.25" would be a good choice given your weight limitation.

The current Celestron coatings are so superior to the coatings in your current telescope that they will help you a lot, too. You'll get more light, but you'll also get more contrast because there won't be so much scattering and stray light. High contrast is worth a lot.

Regards,

Phillip

P.S. The new Meade aplanatic catadioptric telescopes (eg. LX200ACF) have good full-field image quality and coatings, too.

Hi gents,

I have an Orange C-8 and a C-11 Ultima PEC. What I can say is that I always use my C-8 on the planets, due to less trouble with air turbulence.... For deepsky I use always my C-11 because of the "wow" factor.
The C-8 setup time is 2 minutes, hauling with my 73 pounds forkmounted C-11 Ultima is not my favorite thing.....but when I observe I am glad that I have set upmy C-11.

Ido Oosterveld Netherlands

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