22 replies to this topic

[chbrandt]

I'm in the very early stages of planning/saving for some new glass and wanted to get some updated opinions on these two scopes.  Here are the pros/cons I've found listed in old threads for these scopes:

 

Pros of XT12g

Ease/time of setup

Less collimation required

Lighter in weight overall

Significantly cheaper ($453, assuming shroud for XX)

Not affected by elements due to solid tube vs. truss (flexure, wind, etc.)

 

Pros of XX12g

Easily broken down/transported in any vehicle

Cooling fan included ($23 value)

Probably looks cooler

Mirror cools faster if open?

 

Let me talk for a bit about how I would use the scope.  I live in a light-polluted city with an XT8 and since getting into astronomy last March, I've logged exactly 60% of my 100 observing hours with the scope from my house.  The other 40% I've taken the scope to darker skies.  I would say that the percentage of going to darker skies is certainly increasing.  For example, since August, it's been 40% at home and 60% away from home.  Often I'm very limited on my time, observing only for an hour or two, so the grab and go XT8 has been great.  I have a Toyota Highlander and don't expect to ever have a smaller SUV.  I'm 30 years old and currently store my XT8 upstairs but don't really have any trouble carrying 40-50 lbs short distances.

 

Assuming I could talk the wife into a $2,200 budget later this year, I'm between the XX12g and a shroud, OR the XT12g, the wi-fi controller, a cooling fan to match the XX, a padded telescope case and an off-axis solar filter.  The latter option would also save about $40, perhaps for a new telrad.  If I don't need to break the scope down into smaller pieces, is there any way I could justify the XX over the XT?  Are the views in these two truly going to be near-identical?  Interested to hear some thoughts from other users.  Thanks in advance!

[starbob1]

I looked though many 12in Dobs and I would never pay what Orion wants for them when you can get a Zhumell for $700 that the optics will be as good or same. With a budget of $2200 your getting close to having money for a used premium DOB. 

[ron2k_1]

I dream I can soon have my own place and house a truss dob in there.  I'm coveting one of those Explore Scientific 12" Truss.  They look solid and the reviews so far seem promising if you know what you're getting.

 

I don't think I need GoTo and tracking, so I'd never pay Orion their asking price for their units.  But I think I prefer them over Skywatcher - Orion units seem sturdier, better quality materials and better build.

 

Ron

[csrlice12]

Optically, flip a coin.  Of the two, pick whichever one you feel will be less work for you.  Pick the one you're most likely to want to load up and take to a dark site.  Be sure to consider the vehicles you own, who all will be going (or just you), is it the only scope you take, etc.....and remember, you ain't going to get any younger.....and IMHO, the 12" is about the largest scope I'd want to mess with alone.  Bigger then that, it's good to have a friend  (unless you have the $$$ for one of those large f3ish scopes, but then you're talking big bucks outside of my bank account).  AND, most importantly, if married....which one has her approval.........

[REC]

Did you look at the Meade Light Bridge?

[REC]

BTW.....there is an excellent review of the Apertura 12" Dob on CN and although it's no longer available, it is the same as the Zuhmell scopes. The person who did the review is very knowledgeable, John Kramer, take a read in the review forums.

[dr.who]

The truss tube will be overall easier to work with because it comes apart. You many not think so now but in time this will matter. A 12" dob is a great place to be for visual work. Lugging a 12" tube with a mirror in it around can become enough of a pain to where you begin looking for excuses not to use the scope or use your 8" instead.

 

That said there are other options for you if you want the convenience of push to via computer without the motorization of GOTO. If GOTO is not a must but push to is then your options open up quite a bit. And at that price will put you in the premium dob category. Things like the 12" Obsession or Starmaster are options and can be found on Astromart. If GOTO is a must have then the Orion platform is the right one for you unless you can find a used scope on Astromart with ServoCat Jr. They come up occasionally.

[Tony Flanders]

Cost aside, solid-tube Dobs have few advantages over truss-tube Dobs. The main advantage that I can think of is that it's much easier to seal off a solid-tube Dob, meaning that you don't need to worry about the mirror frosting over after bringing it inside in the winter.

 

Solid-tube Dobs may or may not hold collimation better; it probably depends on the scope. As for convenience, that's clearly a win for the truss-tube. After all, you can always store the truss-tube Dob fully assembled, in which case it sets up just like a solid-tube Dob. The reverse is not true.

 

Yes, truss-tube Dobs do tend to have better thermal characteristics, too.

[Jon Isaacs]

Cost aside, solid-tube Dobs have few advantages over truss-tube Dobs. The main advantage that I can think of is that it's much easier to seal off a solid-tube Dob, meaning that you don't need to worry about the mirror frosting over after bringing it inside in the winter.

 

Solid-tube Dobs may or may not hold collimation better; it probably depends on the scope. As for convenience, that's clearly a win for the truss-tube. After all, you can always store the truss-tube Dob fully assembled, in which case it sets up just like a solid-tube Dob. The reverse is not true.

 

Yes, truss-tube Dobs do tend to have better thermal characteristics, too.

 

Planetary observers seem to prefer tube scopes rather than truss scopes because the tube blocks the body heat of the observer better than an shrouded truss.  Daniel Mounsey is quite vocal about this...

 

As someone who has four truss Dobs, one tube Dob, this is how I see it:

 

Tube Dobs are easier to setup and in general better as planetary/double star telescopes. 

 

Truss Dobs take up less space when transporting them, the various pieces are lighter.

 

The fundamental questions:

 

- Will the 12 inch tube fit in your vehicle without a serious struggle? Will it take up space needed for passengers etc?

 

- Does the 12 inch tube represent a physical challenge, lift it, carrying it?

 

If it fits in your car and you have the extra room, if you can lift and carry a 14 inch diameter tube that is 5 feet long and weighs 50 pounds, then the tube Dob is a reasonable choice..

 

If you are 6 foot 2 in, lift weights as a hobby and have a Chevy Suburban and are traveling alone to the dark skies, the tube Dob is a reasonable choice.. If you struggle lifting that 12 inch tube, if you have a Honda Accord and want to take the family with you.. It's definitely time for a truss.  

 

Jon

[chbrandt]

Lots of great input.  Thanks a lot!  Where I struggle the most is, throughout this thread and others on the same topic, I see people who say completely opposite things.  I've read that both truss and solid tube have better thermal characteristics.  I've read that collimation holds better in both.  I read that Orions are great value and that they're awful.  These conflicting ideas are tough to figure.  

 

If I'm going to spend this kind of money, I think having a Go-To is an absolute must for me, even if I would use it much less than the tracking.  Premium dobs with go-to are just out of my price range, unless I'm missing something.  Even from what I've seen used.  

 

If I were to buy a truss tube, I can't imagine hardly ever taking it apart, as I wouldn't need to for transfer.  The problem then becomes, it's significantly heavier in the base, and I don't think I can lift an 80lb base.  That means I'm taking it apart to transfer it every time, and that means I'm losing maybe half of my observing time on a given weeknight to put the scope together.

 

It is very interesting to see the people who think I've stumbled on two scopes that they wouldn't consider for this money, as I hadn't seen that much in other threads comparing these two scopes.  Maybe it's back to the drawing board.

[Jon Isaacs]

Chris:

 

Here's a few thoughts and comments:

 

If I'm going to spend this kind of money, I think having a Go-To is an absolute must for me, even if I would use it much less than the tracking.

 

 

A 12 inch Zhumell is $700 with free shipping. An XT-12G is $1800 with free shipping.  You are spending "this kind of money" to get the GOTO.   It's worth thinking about whether it's worth the $1100 or maybe that $1100 could be used more effectively for something else.  

 

If I were to buy a truss tube, I can't imagine hardly ever taking it apart, as I wouldn't need to for transfer.  The problem then becomes, it's significantly heavier in the base, and I don't think I can lift an 80lb base.  That means I'm taking it apart to transfer it every time, and that means I'm losing maybe half of my observing time on a given weeknight to put the scope together.

 

 

If you are not going to disassemble the truss tube, it makes little sense to buy it.  

 

Thanks a lot!  Where I struggle the most is, throughout this thread and others on the same topic, I see people who say completely opposite things.  I've read that both truss and solid tube have better thermal characteristics.  I've read that collimation holds better in both.

 

 

 

Different folks have different experiences. Some scopes hold collimation better than others. There are a lot of different truss scopes out there.  People can only share their experiences and what they believe to be true.  I can share my experiences along with what I think to be the reasons... 

 

Jon

[dr.who]

Lots of great input.  Thanks a lot!  Where I struggle the most is, throughout this thread and others on the same topic, I see people who say completely opposite things.  I've read that both truss and solid tube have better thermal characteristics.  I've read that collimation holds better in both.  I read that Orions are great value and that they're awful.  These conflicting ideas are tough to figure.

Solid tube dob's are not affected by your body heat bleeding in through the truss's this is why people say they are better. A shroud does help with this heat bleed though. Now truss tubes, because the mirror is more exposed, will cool down faster and maintain thermal equilibrium better because of their design. So this is likely why you hear they are better.
 
As to collimation... There were some problems with holding collimation on certain ultra compact and ultra light design truss dobs. this had more to do with rigidity of the structure than the overall design itself. I had this problem with my own Obsession UC 15. It came with two struts that went on the virtual mirror box. Without them the scope would not hold collimation when moving from zenith to 45*. The ultra compact/ultra light design is a trade off. You are shedding weight and size but are impacted by that loss.
 
On the subject of Orion quality... The Orion series of Dob with GOTO and PUSH TO features are a great value for their price. However they are not considered high end or premium Dobs. The mirrors are mass produced as are the structure and other components. This means that there will be some fantastic samples out there that can give a Teeter Dob with a Zambuto mirror a real run for its money. On the other hand there will also be samples out there that are so bad using a shaving mirror and a paper towel tube will give you better views. For the most part though they will be right in the middle point. Not fantastic but not complete rubbish either.
 
However getting something with similar features from a non-mass produced manufacturer will cost sometimes substantially more. Reason being is the non-mass produced manufacturer doesn't have the economies of scale that Orion does. So again for their price they are a good value.
 

If I'm going to spend this kind of money, I think having a Go-To is an absolute must for me, even if I would use it much less than the tracking.  Premium dobs with go-to are just out of my price range, unless I'm missing something.  Even from what I've seen used.

If you won't use it why spend the money on it? Why not get a premium dob with a premium mirror and push to?
 

If I were to buy a truss tube, I can't imagine hardly ever taking it apart, as I wouldn't need to for transfer.  The problem then becomes, it's significantly heavier in the base, and I don't think I can lift an 80lb base.  That means I'm taking it apart to transfer it every time, and that means I'm losing maybe half of my observing time on a given weeknight to put the scope together.
 
It is very interesting to see the people who think I've stumbled on two scopes that they wouldn't consider for this money, as I hadn't seen that much in other threads comparing these two scopes.  Maybe it's back to the drawing board.

A possible alternative to the Orion for you may be the new Skywatcher Synscan GOTO dobsonian. They are now on the market, they use the Synscan system (Synta the parent company OEM's the Dobsonians as well as the Atlas and Sirius mounts and a few other things for Orion), The tube collapses down into something a bit more manageable space wise, the base is 50 lbs fully assembled, and the tube is 46 lbs.  Also it is $100 less than the Orion truss Dob. Also you won't have to assemble the truss each time since the UTA collapses into the mirror box.

 

By the way the Orion weighs about the same when you separate the truss, UTA, and mirror box from the base.

 

If that 50lbs is still a bit difficult you can put ramps on the rear of the SUV, add wheel barrow handles to the base, and roll it up the ramps into the SUV then roll it back down out for observing.

[Tony Flanders]

Lots of great input.  Thanks a lot!  Where I struggle the most is, throughout this thread and others on the same topic, I see people who say completely opposite things.  I've read that both truss and solid tube have better thermal characteristics.  I've read that collimation holds better in both.  I read that Orions are great value and that they're awful.  These conflicting ideas are tough to figure.

Solid tube dob's are not affected by your body heat bleeding in through the truss's this is why people say they are better. A shroud does help with this heat bleed though. Now truss tubes, because the mirror is more exposed, will cool down faster and maintain thermal equilibrium better because of their design. So this is likely why you hear they are better.

Exactly. Better in some ways, worse in others. It depends on many factors. For instance, a fan may make the whole cooldown issue irrelevant. And body heat passing in front of the tube depends on the prevailing wind.

But I'm a bit skeptical that the body heat penetrates a shroud all that well. As for the heat that passes in front of the entire scope, there's not much you can do about that, except maybe use a big fan to push the air the other way.
 

If I'm going to spend this kind of money, I think having a Go-To is an absolute must for me, even if I would use it much less than the tracking.

I'm not sure what you are saying. Do you want Go To drive simply for locating objects? In that case you would probably be better served by Push To rather than Go To. Lighter, simpler, no vibration issues, needs much less electricity.

Go To as opposed to Push To only makes sense if tracking is really important to you.
 

If I were to buy a truss tube, I can't imagine hardly ever taking it apart, as I wouldn't need to for transfer.

If you won't use it why spend the money on it? Why not get a premium dob with a premium mirror and push to?

Agreed. It seems crazy to spend a lot of money to ensure that your scope can be disassembled and then not disassemble it.

[aeajr]

starbob1, on 01 Feb 2016 - 2:53 PM, said:

I looked though many 12in Dobs and I would never pay what Orion wants for them when you can get a Zhumell for $700 that the optics will be as good or same. With a budget of $2200 your getting close to having money for a used premium DOB.

 

Starbob1, I think  you overlooked that the Orion scopes that are being asked about are full Goto Dobs, something Zhumell does not offer as far as I know.

 

Chris,

 

I am fairly new having entered the hobby only 8 months ago so what I will say here is based on a relatively short experience but a LOT of study and research.  I have the Orion XT8i Intelliscope.  Love it!   The Intelliscope is such an inexpensive added feature to a similarly configured basic XT8.

 

If you want help finding targets and are not concerned with tracking the XT12i Intelliscope would save you about $500.  Intelliscope works great but it will not track.  All up weight about 83 pounds.  50 for the tube and 33 for the base.

 

If I was going to go to a 12G then I would consider the following:

 

Where will I store it?  Where will I use it for observation?

 

• XT12G is 101 pounds, about 50 pounds per piece.  Heavy but workable in 2 pieces if you have space in your car.
• XX12G Is 128 pounds, 47 and 79 pounds respectively.  Heavier but will fit in a smaller car.

I would want these somewhere I could use in place most of the time or could keep on a rolling base.  Orion offers rolling options.

http://www.amazon.co...s/dp/B00B1N74GI

http://marketplace.s...browse-144.aspx

 

If I could not keep it in place or on a rolling cart then it becomes a matter of where you are going to store it.  The truss might work better for you that way.   Likewise if you could not roll it to the observation site then you have to take it in pieces.  Well then I still think I would go for the lighter solid tube.

 

If I was going to put these in a car often and take to remote site then I would opt for the XX in case my car gets smaller or I have to bring other stuff.  If the XT12G would fit and it would be an unusual need to go in the car I would go that way.  But you say you are going to remote dark sites more and more often.

 

In my opinion, the only reason to go to the XX12G is if the solid tube won't fit in your car or storing the tube is a problem.  Cool down time would not be an issue for me as it would live in my garage and would be close to ambient temperature all the time.  A fan would be fine.  In your case it will be in the car during transport and may have a chance to adjust during the trip.

 

I would LOVE to have either one of these.  My wish for my next scope, someday, will be an Orion XX14G.   Why stop at 14"?  Because I can reach the eyepiece without a stool or ladder and it will roll out of my garage on a cart without hitting the garage door.    They don't offer a 14" solid so I would not have an option.

Edited by aeajr, 02 February 2016 - 04:44 PM.

[chbrandt]

When I said I don't know that I'll use the Go-To as much as the tracking, I meant that I'm fine star hopping to objects a majority of the time, but once I'm on them, tracking is a must.  There are definitely times when we're showing objects to the public where I'd like to be able to use the Go-To, but I don't rely on it.  I'm working on the H400 right now and plan to work on the HII after that, so the Go-To could get some use there as well.  Tracking is really something I don't know that I could go without if I'm going to buy a big scope that I plan to use for years to come.  I spend lots of time observing with friends/family and the public, and not tracking can become pretty annoying.  

 

I'll have to look at the SkyWatcher scopes to see if they have an option at this size that tracks.  I've also checked out used StarMaster scopes, which I'd just love to have, but it's hard to find a 12.5 inch with the goto and tracking for that $2k price range.

[Nile]

 

Tracking is really something I don't know that I could go without if I'm going to buy a big scope that I plan to use for years to come.  I spend lots of time observing with friends/family and the public, and not tracking can become pretty annoying.

 

Hmm. If I have to guess, then, while observing with many people, you are probably not aiming for really faint objects. The tougher targets. Not only that, most of your family is not going to have eyes adapted for darkness (going in and out of house/checking phones etc.).  Plus, for friends and family, its nice to show the objects that are bright, big, better looking. Considering all this, a 12" aperture could be an overkill.

 

Save money on aperture and go with a smaller dob with GoTo. 8 inch or 10 inch. That's a significant savings.

 

And, if you really don't want to compromise, then buy a smaller GoTo Dob (say 10 inch) and a 12 inch Zhumell. You will save almost a thousand dollars between XX10 g vs XX12g which will buy you a 12 inch Zhumell and still leave some change in your pockets. (Your wife may ask you to sleep on a patio if you fill house with so many telescopes, but hey, you will be awake at nights at an eyepiece anyway! ;-) )

Edited by Nile, 02 February 2016 - 06:04 PM.

[aeajr]

 

 

Tracking is really something I don't know that I could go without if I'm going to buy a big scope that I plan to use for years to come.  I spend lots of time observing with friends/family and the public, and not tracking can become pretty annoying.

 

Hmm. If I have to guess, then, while observing with many people, you are probably not aiming for really faint objects. The tougher targets. Not only that, most of your family is not going to have eyes adapted for darkness (going in and out of house/checking phones etc.).  Plus, for friends and family, its nice to show the objects that are bright, big, better looking. Considering all this, a 12" aperture could be an overkill.

 

Save money on aperture and go with a smaller dob with GoTo. 8 inch or 10 inch. That's a significant savings.

 

And, if you really don't want to compromise, then buy a smaller GoTo Dob (say 10 inch) and a 12 inch Zhumell. You will save almost a thousand dollars between XX10 g vs XX12g which will buy you a 12 inch Zhumell and still leave some change in your pockets. (Your wife may ask you to sleep on a patio if you fill house with so many telescopes, but hey, you will be awake at nights at an eyepiece anyway! ;-) )

 

 

 

Interesting approach. If there is room to keep the scopes there is some merit to that.  Might not meet Chris's objectives but it is an interesting approach and a different use of budget. 

 

And that is somewhat similar to what I do when I have people over.   I set up the 80 mm Goto and have it tracking a target while I am swinging the 8" Dob.  Periodically I put that GoTo on a new target which it tracks.  I go back to the Dob to show various sights.    Actually works well especially if I have someone who knows how to work the GoTo.  I can give them a list of targets to pick.  I usually have a Zoom in the Goto scope too.

Edited by aeajr, 02 February 2016 - 06:48 PM.

[dr.who]

When I said I don't know that I'll use the Go-To as much as the tracking, I meant that I'm fine star hopping to objects a majority of the time, but once I'm on them, tracking is a must.  There are definitely times when we're showing objects to the public where I'd like to be able to use the Go-To, but I don't rely on it.  I'm working on the H400 right now and plan to work on the HII after that, so the Go-To could get some use there as well.  Tracking is really something I don't know that I could go without if I'm going to buy a big scope that I plan to use for years to come.  I spend lots of time observing with friends/family and the public, and not tracking can become pretty annoying.  

 

I'll have to look at the SkyWatcher scopes to see if they have an option at this size that tracks.  I've also checked out used StarMaster scopes, which I'd just love to have, but it's hard to find a 12.5 inch with the goto and tracking for that $2k price range.

 

Ah! OK! That makes sense! The Meade Lightbridge and the standard Skywatcher scopes are options for you in that case. They both will take a JMI Train and Track system. The Zhumell may as well. I would look into that option since you have the skill to star hop.

 

Tony-

 

I should have said the shroud stops the body heat from affecting the scope.

[chbrandt]

Buying multiple scopes is an interesting thought. I would say my top priority is probably knocking out both Herschel programs, with public service coming in just behind that. The question then becomes how bad do I want tracking when I'm doing my own personal observing vs just having it on a smaller scope. Storage is definitely something to consider. I think I can talk the wife into letting me spend $2200 but I just want to get the best option(s) I can with that. Really appreciate all of the thoughts.

[aeajr]

Is your 8" sufficient to find what you want in the Herschel program?   

 

I don't see a mid size grab and go in your signature.  You might consider something like a 5" Mak GoTo or 4" refractor GoTo for your public service use and stay with the 8" for the Herschel program.

 

Perhaps something like this:

 

Orion StarSeeker IV 127mm GoTo Mak-Cass Telescope Kit - 5" Mak can see a lot.

http://www.telescope...15/p/113918.uts

 

Or

 

Celestron NexStar 102 SLT Computerized Refractor

http://www.telescope...yPriceAscending

 

 

Stay with your 8" dob or sell it and get the 12" XT12I Intelliscope - Computer assisted but not tracking.

http://www.telescope...S&keyword=XT12i

 

Two nice scopes, Goto for public and 12" computer assist for your Herschel program and deeper sky looks.  Essentially the Intelliscope is digital setting circles.  And you are still under budget.   Or go for the fully manual Z12.

 

 

Just a different approach.

[Jon Isaacs]

Buying multiple scopes is an interesting thought. I would say my top priority is probably knocking out both Herschel programs, with public service coming in just behind that. The question then becomes how bad do I want tracking when I'm doing my own personal observing vs just having it on a smaller scope. Storage is definitely something to consider. I think I can talk the wife into letting me spend $2200 but I just want to get the best option(s) I can with that. Really appreciate all of the thoughts.

 

One piece of equipment that has not been mentioned is the Equatorial Platorm or Poncet Platform.  

 

These are an alternative to GOTO mounts and they can provide tracking for over an hour.  After the hour, the platform is reset.  Resetting the platform for the common designs takes approximately 10 seconds. They are low profile so they add little height to the scope, the basic alt-az configuration of the Dob is retained, they are relatively light and can be used with multiple scopes without any fundamental changes. Basically one has a Dob but it tracks.  They are generally configured for one latitude but they can be used at other latitudes with shimming.   They are simple enough that they can be built by the home carpenter.  

 

There are two ways the mount can be used, the complete scope and sit on the platform or the ground board of the scope can be removed and the rocker box sits on the platform, the platform replaces the ground board. 

 

I was lucky enough to buy a top of the line Equatorial Platform along with a premium Dob at an excellent price.  For me, a real virtue is that I can use this particular platform with any Dobsonian up to about 18 inches.  In your situation, the mount could be used with both the 8 inch and a 12 inch scope.  Setup is easy, the platform weighs about 30 pounds, impressive for a mount that can carry and 18 inch scope.  

 

There are not a great number of manufacturers. The big names avoid them because their custom nature.  But there are smaller manufacturers and ATMs that build them, Ed Jones builds equatorial platforms, there is one called the Crossbow, it's under $700,  and a small operation is Atomic Platforms.  The high end is represented by Tom Osypowski's Equatorial Platforms, these are not inexpensive but they are very nice with options like dual axis drives with autoguiding and a hand controller with 2 speed slewing.And there is always the used market. 

 

Like anything, Equatorial Platforms have their advantages and disadvantages.  My goal here is just to provide some information on an other option, something not everyone is aware of.  

 

Below is a photo of my 10 inch GSO Dobson mounted on a Tom O, dual axis aluminum Equatorial Platform. I use it with the 10 inch, the 12.5 inch, the 13.1 inch and the 16 inch.. The 25 inch is too big for it.. 

 

Jon

[aeajr]

Jon,

 

You never cease to amaze me.  With all the reading I have done I have not come across any reference to this mount.   It looks like a "wedge" for dobsonians. Very interesting.

 

And I have that same jumper pack hanging off the side of my workbench to drive the chargers for my model airplanes. 

[johngwheeler]

Jon,
 
You never cease to amaze me.  With all the reading I have done I have not come across any reference to this mount.   It looks like a "wedge" for dobsonians. Very interesting.
 
And I have that same jumper pack hanging off the side of my workbench to drive the chargers for my model airplanes. 

Yes, EQ platforms are a clever idea, and it took me a while to work out how they worked - I had initially imagined a wedge inclined at the same angle as one's latitude, which would be very precarious at anywhere over 40 degrees north/south!

The downside is that they are still a "custom build" kind of thing, from very small manufacturers, and as such relatively expensive. It would great if the major scope makers offered these as options.