C6 or 6" Intes MCT or C6-R?
Posted 29 October 2013 - 05:15 PM
But to make the *right* choice, it depends a lot on what types of objects you want to observe, and where you plan to use the scope most of the time...
Posted 29 October 2013 - 05:24 PM
Which is your preferred scope?
Posted 29 October 2013 - 05:26 PM
It will have better contrast on planets, better deep sky performance, and a far wider true field than these other designs.
A 6" acromat though is not the same thing as a 6" APO.
And don't let people convince you that you can turn a 6" acromat into a 6" APO with a filter. The damage from CA is not just the color fringing, but rather the energy removed from the Airy Disk, which lowers the performance to no better than a 4.5" to 5" ED refractor. The only thing left is the wide field performance.
If you are comparing 6" f/10 MCT to 6" SCT, then because the new Celestron scopes seem to have excellent quality, the difference will not be all that much.
If you like to do planets, an older 6" f/15 Intes will beat anything either of the f/10 scopes.
There is an option between all of these though.
If you can find a used MN66, you get the excellent contrast and wide field performance of a 6" APO, but you still have to ante up for a medium size mount.
So, you are comparing apples to go carts here by including 6" refractors because to get one with good performace, it needs to be an APO and this means that with the mount, you will spend 10 times as much as you would for a 6" SCT.
The big, fast achromats are simply not very good telescopes for much other than wide field, but if that is what you want, and if you can afford the mount, then go for it.
But a used MN66 is such a better scope than all of these other choices, that if you are seriously considering a 6" refractor, do yourself a favor and get the 6" Mak Newt.
Posted 29 October 2013 - 05:32 PM
Posted 29 October 2013 - 05:40 PM
Posted 29 October 2013 - 06:04 PM
Well these are all sort of the same in cost. I could add an 8" f/5 Newtonian to the mix. This should be good for wide fields plus all the above but much bulkier than a SCT or MCT.
All the scopes you mention have their pros and cons. So it all just depends on your preferences in the mix.
A C6-R is a big scope. The mount needs to be tall with legs extended if you are viewing anything near the zenith...otherwise you will be on the ground trying to access the eyepiece. It will do great with most everything, but will show color on planetary or lunar viewing which some folks do not like. You will get a 2.2 degree TFOV as max with a 2" eyepiece.
The SCTs and MCTs are closed tube and will have thermal equillibrium difficulties if your outdoor temps vary much. But they are small and convenient. Most have long focal ratios though so at ther native f/10 or f/15 the most TFOV you will get is 1.75 to 1.2 degrees with a 2" eyepiece...and their central baffles may not allow even that. Higher planetary magnifications though they can be great when in thermal equillibrium, better than the achromat for sure.
The 8" f/5 Newt is the biggest and heaviest probably of the group. It will need a Paracorr if you plan wide field. The nice thing though is that with something like a 40mm XW or 31T5 you can get a good, bright, and large patch of sky, around 2.3 to 2.5 degrees. Exit pupil with the 40mm and Paracorr is a bit over 7mm so better choice would be the 31T5 probably. The f/5 will also have a smaller central obstruction by far compared to that on say the SCT.
So just all depends on what you are after. The extra light pull of the 8" though over the 6" is significant, around 1.8x more light gathering. Extra resoltion as well. I've had all the other types of instruments, and now am experimenting with an 8" f/5 on a GEM mount (having a rotating tube is a must if on a GEM). Right now I am much preferring the 8" f/5 over the others because it has a good wide TFOV capability and gathers enough more light to make stuff like fainter Globs much more interesting than what a 6" SCT or MCT will show. If bulk is no issue then IMO the 8" Newt is best all around, if you want to maximize protability than the Celestron C6 is superb and gives a bright image as well. Would probably also get a .6x focal reducer with it though to flatten some of its field curvature out and give it better wide field performance.
Posted 29 October 2013 - 06:45 PM
Have owned three 6" f/8s, and an MN66 is a far better telescope.
But get what you like. It sounds like you may already have a refractor in mind. They are inexpensive and if you have a way to mount it, then go for it.
And if you decide you want to sell it, there will be someone else that will take it off of your hands.
Posted 29 October 2013 - 07:12 PM
Frankly, I probably use the 8" Newtonian the most. It has exceptional optics, and *enough* aperture to do double duty for either lunar/planetary, OR DSO's...
But when I want to get more serious about DSO's in general, I'll always choose the 12" (and it does put up superb lunar/planetary images as well). On the other hand, if I were to choose just the Double Cluster (a personal favorite object which I can easily spend an entire night on alone), I'm about as likely to grab any of them... Each one delivers the goods in their own special way...
But then, there's the 10" SCT, which also has excellent optics (replacement optics for the original set), can deliver stunning images (I do pay meticulous attention to collimation & getting & keeping the optics fully equilibrated with the surrounding air), so, given it's compact size for the aperture, and great images, it could steal your heart when the conditions are right...
I guess I sounded like a politician, there... Never gave you a clear-cut single answer... That's because I'm always wavering back & forth between my scopes as to which is my favorite...
BUT, if I can only recommend one of them, I suppose it'd be the 8" Newtonian, assuming you take the time to assemble one with equal optics & mechanicals...
While I was gone, I see you've also received some superb assistance from others here. This is a GREAT place to come for answers to questions like yours... Some very really well-experienced and helpful folks give of their time selflessly to help flesh out a variety of possible solutions. Hard to find a better place for that than here.
Posted 29 October 2013 - 10:55 PM
Directly to your interests, the messier objects and planets from an urban back yard, from the specific telescopes you have asked about, I'd probably recommend the Intes (or Intes Micro) MCT, if it's an f/10 (the f/15 would be slightly better for planets, and the f/10, with it's wider field, a bit better for the Messier Objects. The C6R would be no slouch on the Messier objects, either. But the other two would probably edge it slightly on the moon & planets, though it would be close.
For a a modest sum more, though, you could buy an 8" SCT, or a REALLY nice 8" f/6 Newtonian (which will take you deeper on the DSO's, show more planetary detail)... Those pesky Newtonians, if assembled from the right parts, deliver amazing views that, with the aid of a Paracorr, can deliver images you'd SWEAR were from an APO.
Posted 30 October 2013 - 12:30 PM
the refractor is long and will need a decend mount so it will weight abit, but its good overall it has some colour but decent optics and vies
the mak will take longer to cool down and long FL means crisper views but fov is small, cooldown time may be 1 hr to 1.5 hrs
sct will be maybe the middle of both the other scopes so my option will be this one for u
Posted 30 October 2013 - 12:33 PM
The SCT is more compact, and can deliver great images. They can be a little slow to equilibrate, compared to the Newt or refractor, but active cooling can be a big help, if the scope has this, or if it can easily be added. And the compact size can be a real blessing during setup and takedown.
The Newt will deliver slightly more aesthetically pleasing images, and a wider field for DSO's, at the expense of a longer tube. And, the Newt, if it's similar to mine, will also be a little more expensive (much of which comes from the Paracorr & Nagler eyepieces, and not the cost of the scope, but without which a level of the superior aesthetics would be lost).
The MCT will have superb views, similar to the Newt, with sharp images across the field, at low or high magnification, and no visually meaningful aberrations. It is compact like an SCT, but more expensive, and cooldown will be as long as an SCT or longer. If you're patient, and don't live where the temperature changes dramatically in a short time, they can be stunning.
Posted 30 October 2013 - 12:37 PM
Posted 30 October 2013 - 02:45 PM
For the money I could get a C8 or C6R.
A C8 (8" SCT) is, IMO, a *FAR* superior telescope to a C6R.
First of all the obvious: It has higher light grasp and resolution. Contrast is comparable. It has no false color unlike the *ginormous* false color of the C6R.
But there are the less obvious as well:
1) The C8 you can observe in comfort seated. The C6R will put you in all kinds of contortionistic positions.
2) The C6R requires a bigger mount than the C8. A CG-5 will hold a C8 like a baby, but trembles under the C6R.
The one advantage the C6R has is larger field of view.
Frankly, the main C6R appeal is that it's cheap. If you can afford something else, go that way.
Posted 31 October 2013 - 02:26 PM
Also with UHC or OIII filter will C6-R be same as an 6" APO?
Posted 31 October 2013 - 02:36 PM
Posted 31 October 2013 - 03:28 PM
You can get fairly close with a Chromacor, but they aren't in regular production any longer, to the best of my knowledge, and aren't inexpensive (except in comparison to the price difference between an achro and APO telescope)...
Posted 31 October 2013 - 08:14 PM
I haven't done it specifically with that 6" achro but if you are entertaining ideas of great 300x shots of Plato or Mars you might want to lose the achro idea all together - certainly at that focal ratio/aperture. There are too many other far better choices.
Posted 31 October 2013 - 08:59 PM
Posted 01 November 2013 - 09:41 AM
Sure cool down is something you have to be aware of, but that is the case with all scopes. Eddgie is right about the MN66. In the 6" class, you will not find a more versatile and optically excellent scope for the money (especially if you find a good one with an upgraded focuser on the used market).
Posted 01 November 2013 - 10:44 AM
Used, they represent a great bargain.
Posted 01 November 2013 - 02:19 PM
I've seen in a non-refractor design. Also, they are lighter
than the Intes MN61, so less of a mount is needed for it.
Posted 03 November 2013 - 06:09 PM