Which is better for DSOs?

[Manok101]

As some of you have probably noticed, ive been asking a lot of questions about telescopes because I want my next one to be my primary scope when I get the chance to observe. I've been considering two types, I'm almost set on an Orion XT10G, but I'd like to ask about Schmidt-Cassegrain scopes. Would they be any better at DSOs, about the same, or what? I do like looking at planets, but my primary observing time is looking at and for DSOs. The main reason I am considering a Schmidt-Cassegrain is the portability over a dob, but I have experience with dobs, and love them so I want some opinions from those who have gotten to use both types of scopes. Please let me know if I am being confusing, I have a tendency for it.

[sixela]

Well, to be honest, I find a 10" SCT less portable than a 10" Dob. More compact, more convenient to store, but a lot heavier, even on a fork mount (let alone an EQ6 and counterweights.

They wouldn't be better at DSOs. About the same for most of them, except or the largest ones (which are viewably in their entirety in an 10" f/5 scope with a large 2" eyepiece but not in an SCT).

I do find an SCT plus a good observing chair more comfortable than a 10" Dob, though. Except if you have a really good observing chair with the Dob, with a very large height adjustment range, and don't mind observing unseated very close to the zenith.

[Moonshane]

I have never used an SCT but totally agree with Sixella about portability from the ones I have seen images of. I also previously used a reasonably large refractor and this with the mounts etc was less (or only as) portable and took up a lot more space then my 12" dob.

I also agree about the importance of an observing chair. anyone could make one of these http://stargazerslounge.com/members-equipment-gallery/97962-observing-chair.html

[ollypenrice]

I feel 'boxed in' by the long FL of the 10 inch SCT and would prefer a faster reflector for DSOs. Also the 10 inch SCT is very heavy and hard to carry. On the planets I don't find it as good as a five inch apo.

Olly

[John]

I agree with the others - a properly mounted SCT is more awkward to move around than a dob of the same aperture. The dob is better for DSO's and, when I moved from an 8" SCT to an 8" F/6 dob, I found that the dob could produce just as nice planetary views as the SCT, when properly collimated.

[sixela]

totally agree with Sixella

Sixela is Alexis in "Zorglangue". Alexis in French == male.

If people start calling me Sixerella they're going to be even more confused about my gender...

[brantuk]

I like both scopes so I got one of each. They're both equally a pain to move around even though one is smaller than the other. Both are fairly weighty beasts.

[CGolder]

I had a 10" reflector on dob and moved to a 10" sct and find the performance very similar, the SCT gains an advantage to me by the viewing position is always perfect. my dob always seemed to put me in a bad position and I would have back problems.

I find that the set up time faster on the dob but not by much.

The decider along with the back issues for me was that the angle of the dob as it sits so low to the ground the trees on the boundary got in the way a lot more.

The dob base is a nightmare to transport around in the car on the sky watcher solid tube and was defiantly less portable, i can just strap the entire folk mount and tube in the seatbelt and then just the tripod. I would have to dissemble the dob base to get it in with the camping stuff.

[pvaz]

Skywatcher also haves GOTO dobs and they are collapsible making them more compact for transport/storage. The extra cost of an SCT will also allow you to get some nice extras or a larger apperture dob so, unless you have a very good reason to get a SCT, the dob seams the to have most of the pros on it's side.

[Manok101]

thanks for the advice, I've got my heart set on a decent sized scope now that I'm hooked on astronomy, I've got a little XT4.5 now, and want to get as much aperture as i can afford.

[Moonshane]

Sixela is Alexis in "Zorglangue". Alexis in French == male.

If people start calling me Sixerella they're going to be even more confused about my gender...

sorry again Sixela

I think it comes from my studies of the latin names of moths where many names end with 'ella'.

[sixela]

No prob (you should see my last name; if I had to be angry every time that was spelled wrong I'd have died of anger by now); I just wanted to point it out before it starts spreading .

[LukeSkywatcher]

Sixela is Alexis in "Zorglangue".

Zorglangue?

Never heard of that before. Which country/region is it from?

[umadog]

I'd vote Dob. You'll get a larger field of view, which is always nice for extended DSOs. Say you put a 31 mm Nagler (extreme, I know) on the XT10. That will give you a 2.1 degree FOV. In a Meade SCT that same EP will give you 1 degree. Don't forget that the Dob will cool faster and it's cheaper. Disclaimer, though, I've never used an SCT.

As for observing comfort. I observe with my XX12 sitting on a common plastic garden chair. I can "sit" on the back of the chair for objects near the zenith, on the arm for slightly lower elevations, and on the seat of the chair for the really low ones. No back issues when using the garden chair and It's perfectly comfortable. Proper observing chair would be even better, of course.

[Manok101]

No prob (you should see my last name; if I had to be angry every time that was spelled wrong I'd have died of anger by now); I just wanted to point it out before it starts spreading .

My last name is so obscure that spell check tells me its wrong even when I spell it right.

[brianb]

Dobs are great at low power. Some DSOs require medium to high power; for planetary nebulae and many of the fainter galaxies, field width is not an issue.

I don't think there's much difference in pritability between my CPC1100 and a 12" Dob ... the CPC1100 is more convenient and the tracking compensates for the aperture defect. I went through this and decided in the end that the CPC1100 was, for me, the best scope I could handle ... if money had been more of a factor this would have tipped the scale towards a Dob. But then I wanted an all-rounder capable of planetary imaging....

No regrets about the decision except that at the moment I can't use my CPC1100, being unable to lift it with a broken wrist. Same issue would stop me using a 12" Dob.

With a 10"+ scope you do however "need" a small scope - preferably altaz mounted - for use as a "grab 'n' go" and for wide field objects which the larger scope won't handle. (Personally I find the secondary shadow in the exit pupil very distracting with reflectors when the power is less than about 6x per inch, and ultra wide field EPs don't compensate for the coma inherent in fast Newts). A 80-110 mm refractor is ideal for the second scope especially if you have an interest in solar work too; if the sun doesn't interest you then a 4-5" Newt on a Dobsonian mount will do great.

[Sam]

I've got two "big dobs" one's a 16" and the other is a 10". I use the 10" for imaging and the 16" for observing. I've mounted the 16" on wheels so it's very easy to move around. I have no problems cranking the power up and as long as it's well collimated the views are fantastic. Portability is only an issue if you have to take your scope somewhere else, if it's just in your garden and there's no stairs to worry about between your observing site and where you store your scope then upsizing your scope is well worth it.