View Full Version here: : Visual - C11 XLT or C11 Edge

18-08-2017, 01:08 AM

I'm considering getting a C11 mostly for DSO and a little planetary viewing.
No Astro-photography needs here what so ever.

Question is.
Would I really notice any difference in a EdgeHD when compared to just a standard XLT?

18-08-2017, 05:21 AM
I use the C11 XLT.....
IMO visually it performers very well. No need for the Edge version.

18-08-2017, 06:34 AM
agreed, and I have used both :thumbsup:

18-08-2017, 08:43 AM
For mostly DSO use and especially with a low power, wide angle eyepiece the Edge is far better than a standard SCT. The outer field has large amounts of coma and field curvature in the SCT.

The Edge vents make cooling easier too: you can buy the expensive Tempest fans or strap a computer fan over one of the vents.

Big difference in price between the two scopes though.

Another option is the 10" Meade ACF; less light grasp than the C11 but just as good visually as the Edge.

18-08-2017, 11:06 AM
+1 Yeah I'd go with the Edge...oh wait, I did :lol: I know wide field is not what we buy a 11" cat for, but you'd be surprised...~1 degree with a decent 40mm eyepiece, more with the (also pricey) reducer.

18-08-2017, 12:29 PM
This is something you need to decide for yourself. Everyone has their opinion one way or another.

In a standard SCT, ok, you have very little distortion when pushing it to its absolute widest TFOV say with a 30mm 80 eyepiece. For visual, really so what? You DO NOT do serious observing at the edge of the FOV. No one does. And as you are constantly changing eyepieces, the edge of the FOV is not a concern. More significant is eyepiece selection which makes the world of difference with ALL scopes. Chose the right eyepiece for each scope design! You may find you never needed that corrector if you had the right EP for the scope you are using.

But this is very much an individual preference. I have fast Newts, and I don't use a coma corrector, and I'm pushing two, three hours on a single object as I sketch, and my Newts are all push-pull. But I am using the right eyepieces for my fast Newts!!! And my lowly 8"SCT by comparison shows bugger all edge distortion compared with my Newts. I also have eyepieces that I use exclusively on my SCT that are not used in my Newts. Sorry Dunk, I love you mate, but give me those photons that are gobbled up by those correctors every time... :lol:

However, this is ME in my choice to not use a corrector. For some people it is more of a matter of because the gizmo is there they'll use it. Which really is fine too. Some insist on a coma corrector, I have no need for one.

Where it IS IMPORTANT with SCT and Newts alike is with photo. Then it is mandatory to use the appropriate corrector or even purchase a factory corrected instrument or the edge of your photos will be stuffed.

Where some people confuse things is mixing photo applications with visual which is much more forgiving due to our human eyes and how we use our scopes which is very different from photo.

So, what's important to YOU?! We can offer you only our opinions and experience. And not one single one of us is either right or wrong or absolute. Just understand that the "which scope equation" has a huge human factor in it that is multi faceted - oh, and do not forget the eyepiece component in this equation too...


18-08-2017, 02:06 PM

Only issue I'd suggest you consider is the size & weight, and the practicality of it if this is going to be a transportable scope. An 11" is quite a significant increment compared to an 8" SCT.

I've known a couple of older blokes downsize from 11-12" SCT's as they were just not able to handle them safely anymore.

Optically...on an 11" the seeing will be the main limitation so most of the time I don't think you'll be able to tell the difference between an EdgeHD vs standard C11.

18-08-2017, 07:13 PM
Thanks Guys.
All great feedback.

I know its very opinion oriented but with no way to look through both and compare its all I got.

I was thinking as suggested it may be better to get the 11" standard and dump the money I save into 3-4 good eyepieces and a better diagonal.

the only thing at the back of my mind. Will I get upset with coma at the edge after I have invested in it.

So anyone in Perth got an 11" XLT they setup from time to time I can look through?

19-08-2017, 12:15 PM
It's not just the coma in a standard SCT, it's the field curvature.

If you're visual only, take a look at the CPC 1100 Deluxe HD that Bintel have on offer - looks much better value IMO. The CPC is not wanting...it's solid (and heavy!) but easy to use, setup is easy, and they track well. For the extra few 100 $$s it's wel worth it.