C9.25 or C11?

[Tomjo59]

Hi all.

I am considering buying a Celestron C11 SCT, and just wondered if anybody has any opinions regarding their performance as compared to the C9.25, specifically for lunar and planetary work?

I have often read that the C9.25 is a bit 'special' in this regard, and wonder if it is worth foregoing the larger diameter (and saving money). Or is the larger aperture going to perform better anyway BECAUSE its larger?

My main interest will be in visual observing, but may want to try imaging later.

I have gone for an SCT because I will want to observe DSOs as well, and also the physical size would be a lot more convenient; otherwise I might have gone for a Newt.

Tom

[nightfisher]

heard a lot of good things about the 9.25, and as it stands its pretty good aperture

[riklaunim]

9,25" isn't that much special. It has slightly slower mirrors (f 2,3 instead of f 2 if i remember correctly) thus it illuminates bigger sensors bit better. I have C11 and it performs very nice on planetary and lunary imaging. It's getting heavy but still I'm capable to use one hand on it

Check prices before buying. SCT Celestron prices gone crazy in Europe and there may be big differences between shops or countries. Check for example:

Sky-Watcher Schmidt-Cassegrain)

Celestron Optical Tube Assemblies

[Revs]

I think people like the 9.25" because it's good value, but the 11" should out perform it in resolution.

[dweller25]

If you want a scope for visual planetary then a good 8" or 10" Newt will be sharper and cheaper than a 9.25" or 11" SCT.

[ollypenrice]

Have a look at Damian Peach's website. From memory he said the C9.25 gave similar results to big brother. I think there is a review of his on there.

Olly

[Tomjo59]

Thanks, Olly.

Mr Peach's site certainly answers many of my questions, and there aren't many better authorities than he!

[insky]

I think perhaps the few first things to ask you’re self

Would be

1. Cost

2. Portability

3. Do you have a mount that can handle the OTA The telescope that is

4. are you just starting out in astronomy or are you a dew soaked trooper

Both scopes are fantastic actually most of the celestron line up are all great.

I my self would lean towards the 9inch scope but that would be my choice

Due to all the other gear I have

I look at portability and ease to use set up and breakdown

If you’re just going to do mostly planetary and moon observing

You would be very happy with a scope in the 6 to 8 inch range

You can still tickle faint detail in some of the fuzzes too

And the money you would save you could invest in your eyepiece box

A nice scope is great but if you only have a few eyepieces

[Mr Spock]

Here's a review I did of the C9.25 a while back http://stargazerslounge.com/equipment-reviews/130266-celestron-c9-25-review.html

Nothing has changed since then. There's no way I would go back to my 10" Newt, or even move up to a 12". Only 16" plus would tempt me away.

I wouldn't swap it for a C11 either. I would go for a C14 though if I had the cash.

[ollypenrice]

Here's a review I did of the C9.25 a while back http://stargazerslounge.com/equipment-reviews/130266-celestron-c9-25-review.html

Nothing has changed since then. There's no way I would go back to my 10" Newt, or even move up to a 12". Only 16" plus would tempt me away.

I wouldn't swap it for a C11 either. I would go for a C14 though if I had the cash.

...and the mount!

So would I, by the way!!

Olly

[CeeDee]

I have my C11 SCT OTA for sale. It's in excellent condition with loads of extras. Can't get it up on my CGEM mount anymore due to a shoulder injury and subsequent operation.

For a fully illustrated info sheet contact me on chris@drage.co.uk

[cgarry]

If you want a scope for visual planetary then a good 8" or 10" Newt will be sharper and cheaper than a 9.25" or 11" SCT.

Is this really the case? If so, what are the reasons for this?

Cheers,

Chris

[CGolder]

Is this really the case? If so, what are the reasons for this?

Cheers,

Chris

I see no reason why the views in a newt are sharper than those in the same size SCT. I have compared a 10" newt with a 10" SCT and couldnt chose between them. Cheaper yes.. but optically the SCT should show less visual issues due to the slower optics

[ollypenrice]

I see no reason why the views in a newt are sharper than those in the same size SCT. I have compared a 10" newt with a 10" SCT and couldnt chose between them. Cheaper yes.. but optically the SCT should show less visual issues due to the slower optics

...welll... the SCT has an extra layer of glass but should have less coma. It really comes down to convenience and whether or not you want the option of a wider field. I'm normally rather indifferent to SCTs but last night the 10 inch was stunning on Saturn so I'm feeling generous!

Olly

[Ad Astra]

...welll... the SCT has an extra layer of glass but should have less coma. It really comes down to convenience and whether or not you want the option of a wider field. I'm normally rather indifferent to SCTs but last night the 10 inch was stunning on Saturn so I'm feeling generous!

Olly

Yes, an SCT has an extra layer of glass up front, but if you want anything like the same magnification, you will probably need to barlow up your Newtonian - so there goes your advantage. If you reply that "I just use the 'super-duper' 3mm lens, I'd just suggest that you check it - many of these lenses are simply lower focal length eyepieces with the barlow built in. And FWIW, when a barlow gets even a little dirty, it loses much more light than a dusty corrector because the light is more diffuse, and each dust grain on the corrector intercepts a much smaller portion of the light cone than it does on the surface of a barlow.

More than any of this silliness, collimation and a good figure are most important. The advantage of an SCT is portability, and a sealed, more maintainence free design. For planetary work, I'm not sure if the C-11 would do much better than the C-9.25, on DSO's of course, it is another story.

Olly & Mr. Spock, "be careful what you wish for" regarding the C-14!!! I have that mount, and it is a beast. Tripod = 25 Kg, EQ head = 44 Kg, Counterweights (2) at 10 kg each, and all that is before you add your OTA of choice (another 22 kg in my case). Not what most people consider to be a "One-Man" scope. But if you are willing to put up with the mass, or you have a permanent place for it, the mount is a wonder.

Dan