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Orion XT10 or XT8?

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#1 Observer2006

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Posted 08 April 2020 - 10:33 PM

For a while now, I have been thinking about upgrading to a better telescope, I currently have a Celestron 90az, which was fine as a starter scope but, I find myself wanting something I can really enjoy astronomy with. So, after doing extensive research I have narrowed my choices down to the Orion XT8 or XT10. Now here's the thing, i'm operating on a very limited budget, and spending the extra 200 dollars on the 10 is going to mean some major compromises in other areas, and, especially having only a 10 and 20mm eyepieces, I wonder if it wouldn't be best to save the money for accessories like eyepieces and filters? What would you recommend, is it worth the extra 200 bucks for more light gathering ability, or should I save the money for other things??



#2 lonn

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Posted 08 April 2020 - 11:02 PM

Get the 10in If you dont you will always wished you had. The 10 and 20mm eyepieces will get you started.


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#3 river-z

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Posted 08 April 2020 - 11:05 PM

Well if it was me I’d get the 10 because you’ll have years to get better eyepieces and whatever else you want. But you can’t make an 8 inch aperture turn into a 10 inch... just my 0.02
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#4 justfred

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Posted 09 April 2020 - 12:00 AM

I'm going with the 8 inch. A lot easier to store, transport, and - most importantly - to set up. You'll use an 8 a lot more than you will the 10 and because of that you'll "see" a lot more stuff with the 8.

 

Now - all that said - you're going to get the 10". :-) Everybody does....

 

Go ahead and get it out of your system. You will have a baseline to make all future decisions against and this is worth its weight in gold.

 

You will enjoy either one. 

 

So, Fred - wait a minute: you've got an 11" Starmaster. Yep. It's the club scope and we keep it at my house. Why? Nobody else has room to keep it ( or the other club loaners) at their place - and the StarMaster EL is pretty compact (and the Zambuto mirror is killer!) I love that scope but honestly its the least used scope of the ones I use. The majority of my viewing is from here at the house and is in the quick-peek category.

 

As a matter of fact, someone donated an old 6" Criterion Dyna-Scope before the stay-at-home orders were issued and I'm in the process of building a dobsonian base for it's excellent OTA. Whole thing will be super easy to set up and use that way and you'll be able to swap back to the GEM if you're in a setting circle mood. I can have a lot of fun with a 6" scope (and if I'm honest there's not a lot more hassle involved with an 8").

 

At this point in the hobby you can't make a wrong decision. You can always sell/swap/trade for something different down the road.

 

Let us know how it goes!

 

Fred


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#5 starblue

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Posted 09 April 2020 - 12:28 AM

The 8" Dob would be lighter and easier to set up and would be a fine scope. However, my opinion is that globular clusters don't really begin to strut their stuff until you have a 10" scope. You'll note I have the XT10.


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#6 MrRoberts

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Posted 09 April 2020 - 05:11 AM

I have told this story a few times here on CN's, but what the heck smile.gif 

About 10 years ago when I first started my astronomy interest, I bought a XT8Plus and joined 2 clubs near me. Went to a couple of star parties and outreach events with the groups shrtly after joining. Although I always liked my 8" (sort of miss it still) I had the opportunity to see through both the XT10i and XT12. I was surprised at how much more could be seen with the 10" than my 8"and the family with the 12" was surprised at how little the difference was between the their 12" and the 10" in addition to the smaller/lighter package. If I am ever given the chance to move somewhere where I can add another scope to my collection it would be a 10" dob. At my age, size and weight are still doable. Teeter had a nice STS 10 I  coveted, wish he was still taking orders.

But the mass marketed units have improved over the years. So if cost/size/weight are the issue definitely go with the 8" and save for raci, observing chair and a couple of better ep's. After your 90 it will give you views to wonder at for many years waytogo.gif 



#7 Jacques

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Posted 09 April 2020 - 06:01 AM

I'd get the 10". You can always gradually upgrade your accessories later. A 10" is not much bulkier than an 8" yet it is a lot more capable. I had both and see myself adding a 10" dob again somewhere in the future. 


Edited by Jacques, 09 April 2020 - 06:02 AM.


#8 starbob1

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Posted 09 April 2020 - 06:32 AM

Get the 10in.



#9 turtle86

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Posted 09 April 2020 - 07:02 AM

Another vote for the 10”.  Much easier to add a couple of eyepieces later than to upgrade to a bigger scope.



#10 Jon Isaacs

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Posted 09 April 2020 - 07:05 AM

For a while now, I have been thinking about upgrading to a better telescope, I currently have a Celestron 90az, which was fine as a starter scope but, I find myself wanting something I can really enjoy astronomy with. So, after doing extensive research I have narrowed my choices down to the Orion XT8 or XT10. Now here's the thing, i'm operating on a very limited budget, and spending the extra 200 dollars on the 10 is going to mean some major compromises in other areas, and, especially having only a 10 and 20mm eyepieces, I wonder if it wouldn't be best to save the money for accessories like eyepieces and filters? What would you recommend, is it worth the extra 200 bucks for more light gathering ability, or should I save the money for other things??

 

Observer 2006:  Hello and welcome.gif to Cloudy Nights.  

 

You have chosen two very capable scopes, scopes that are very similar in both easy of use, ease of setup, as well as capability.  They are more the same than they are different and you can't really go wrong with either one.  

 

I like Dobsonians and own several.  I've had a few 8 inch F/6 Dobs and have owned my 10 inch F/5 for 17 years.  This is the way I see the differences:

 

- Capability:  The 10 inch gathers almost 0.5 magnitudes deeper and has 25% greater resolving power.  This is significant but not as significant as it might seem.  

 

-  Optical differences: 

 

The 10 inch is F/4.7, the 8 inch is F/6.  This means the 10 inch has greater "coma", Coma is an off-axis aberration (away from the center), stars have tiny tails on them. 

 

The 8 inch is easier on eyepieces. With faster focal ratios (F/4.7 is faster than F/6), eyepieces show another off-axis aberration of their own, Astigmatism.  The same eyepiece in the 10 inch will show more astigmatism. 

 

The collimation tolerance for the primary mirror is "laxer" for the 8 inch F/6. The 10 inch requires the collimation of the primary to be double the precision.

 

-  Portability, ease of setup and use:  This depends on your personal situation.  In terms of physical size, both scopes are very close in length, the bases are very similar in size. The 10 inch OTA is larger in diameter and weighs about 50% more, a bit over 30 lbs versus a bit over 20 lbs.  For some people, this is a big deal, for some, it's doesn't matter much.  

 

For me, picking up the 10 inch OTA and carrying it 50 feet is no big deal.  I am 72 years old and one of the 6 ft, 200 pound plus guys.  On the other hand, I have a friend who is younger by almost 20 years who is on the smaller side who cannot manage the 10 inch.

 

- These are both big scopes, physically and optically.  They will fit in most cars but take up a significant amount of room.  This photo shows three scopes, a GSO 10 inch F/5, a Discovery 12.5 inch F/4.06 and an Orion XT-8. 

 

6004392-3bears2.jpg
 
- My recommendation:  
 
I think both scopes are good choices, both have their pluses and minuses. I am not going to tell you which one to buy.  I prefer the 10 inch over the 8 inch but I am an experienced observer and the 10 inch is very manageable for me and I have the experience and equipment to make it perform. Starting out, the 8 inch is just more forgiving. 
 
The one piece of advice I will give:  You can afford either scope.  Choose the scope that seems the best choice in the long run.  Decent eyepieces are inexpensive and while it might be somewhat frustrating in the beginning to have a limited number of eyepieces, as time passes, you will acquire more and more eyepieces. If you choose the 8 inch, you will have some eyepieces but in the long run, you can't upgrade the 8 inch to the 10 inch.  
 
So, if the 8 inch seems like the right scope, buy it but don't do it to save a little for eyepieces.
 
And you have a joyous journey ahead,  I am jealous.
 
Jon

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#11 Observer2006

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Posted 09 April 2020 - 07:53 AM

Thank you all for your responses, I think I'm going to go with the 10, I can always upgrade eyepieces later down the road.


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#12 Jon Isaacs

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Posted 09 April 2020 - 08:06 AM

Thank you all for your responses, I think I'm going to go with the 10, I can always upgrade eyepieces later down the road.

:waytogo:

 

The CloudyNights Classifieds is a good place to get eyepieces..

 

Jon



#13 Tank

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Posted 09 April 2020 - 10:53 AM

10" IMHO is is a much better scope for a extra few $$$

8" is more for people that think they cant handle the 10" or not as serious or more beginner

 

10" Optically will be fantastic

enjoy

 

Eps and accessories you can always add

to be honest 2 EPs and a barlow will pretty much cover 80%-90% of viewing needs

5mm

10mm

15mm

30mm



#14 25585

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Posted 09 April 2020 - 11:24 AM

8" F6 as Jon says will be easier to collimate & should need it less. Less coma means no need to think of a corrector. Slower at F6 means less expensive eyepieces will nit compromise your views.

 

10" F5 is a big-little scope. Its a bit more particular for needing collimation exactness. With your 2 starter eyepieces, Plossls, coma will not be a problem, but its tube is 12" diameter, and mirror particuarly is.

 

If you are tall, Orion make a Dob Pod stand that will take either, but the 8" is probably more suited to it as you will be raising the centre of gravity.

 

If in doubt, go for the 8" Plus model, or an ES Firstlight 8" F6 which has a better mount. 



#15 BDS316

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Posted 09 April 2020 - 12:34 PM

The 10 inch at f/4.7 will require more expensive eyepieces than the 8 inch at f/6.  Less than f/5 is very demanding on eyepieces.  

 

Inexpensive, sharp to the edge in fast scopes, wide apparent field of view... pick two because you can't have all three.


Edited by BDS316, 09 April 2020 - 12:36 PM.

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#16 junomike

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Posted 09 April 2020 - 12:57 PM

Another option is a collapsible 10"

Easier to mange although requires a Shroud



#17 Observer2006

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Posted 09 April 2020 - 12:59 PM

Not sure if I should start a new thread for this but, I have a second question. After shopping around more today, I have realized that possibly I shouldn't go with an Orion Dob at all. I understand the Zhumell Z10 has vastly superior accessories, but is there any major quality difference in the telescope itself?? Is the Z10 a better choice than the XT10? Is there a completely different brand I should consider?


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#18 starbob1

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Posted 09 April 2020 - 01:29 PM

I agree Orion are a higher price. I just got the Apertura 10in with a GSO Mirror ' And its made in Taiwan not China. Check High Point Scientific ' their in stock on sale for a great price. Also all these scopes comes with cheap acessories by the way. Thats why the Basic Apertura DT only comes with one Ep's. You dont pay a $150 extra for a bunch of junk/.



#19 Jon Isaacs

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Posted 09 April 2020 - 01:30 PM

The 10 inch at f/4.7 will require more expensive eyepieces than the 8 inch at f/6.  Less than f/5 is very demanding on eyepieces.  

 

Inexpensive, sharp to the edge in fast scopes, wide apparent field of view... pick two because you can't have all three.

 

I would say it differently.  With the same eyepiece,  an 8 inch F/6 will show somewhat less off-axis astigmatism than a 10 inch F/4.7. What is acceptable varies with the individual. In General, the widerer the field, the sharper stars you want off-axis, the more you pay.

 

My "best" set of eyepieces are all excellent in this regard but simpler, less expensive eyepieces can still be quite good and basic eyepieces, despite some less than perfect views are still enjoyable and productive/effective.

 

Jon


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#20 SteveG

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Posted 09 April 2020 - 03:20 PM

Not sure if I should start a new thread for this but, I have a second question. After shopping around more today, I have realized that possibly I shouldn't go with an Orion Dob at all. I understand the Zhumell Z10 has vastly superior accessories, but is there any major quality difference in the telescope itself?? Is the Z10 a better choice than the XT10? Is there a completely different brand I should consider?

Optically no, they will be the same. Mechanically, I prefer the GSO variants (Z10) over the Orion dob’s. Both are very good though.



#21 Bonco2

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Posted 09 April 2020 - 04:14 PM

Me thinks the original poster has made up his mind. If there is something to be learned from this thread it's that the current 8 inch and 10 inch Dobsonian telescopes are very capable. Both can provide a lifetime of enjoyment. While either can be a good beginners telescope they also are useful and enjoyable for experienced observers.
For older buyers I'd suggest if your back doesn't like carrying heavy objects, the 8 inch might be the better choice. I loved my Z10 but recently I wasn't using it much. The base which is rather large was hard to carry comfortably. So I sold it to buy an XT 8. I've not regretted the decision. My recommendation for someone that has no physical limitations, go for the 10. But both the 10 and 8 can provide so much to a dedicated observer.

#22 justfred

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Posted 09 April 2020 - 05:32 PM

One thing to consider in your choice is what kind of azimuth bearing surface each one has. I like the teflon/ebony-star but some utilize a "lazy-susan" system with ball bearings. FYI.

 

Fred


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#23 junomike

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Posted 09 April 2020 - 06:05 PM

Not sure if I should start a new thread for this but, I have a second question. After shopping around more today, I have realized that possibly I shouldn't go with an Orion Dob at all. I understand the Zhumell Z10 has vastly superior accessories, but is there any major quality difference in the telescope itself?? Is the Z10 a better choice than the XT10? Is there a completely different brand I should consider?

Looks like a decent deal!



#24 anaconda44

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Posted 09 April 2020 - 09:46 PM

Apterura/zhumell are exactly the same scope.  I would not buy from Amazon. Seen reviews on there site where they screw up orders and you only get the base  or tube. Instead of both packages.  Buy from explore scientific. Com. They even give you a 5 years warranty from them. Plus amazon is way behind on orders more chance they will screw up and leave you with hassles and no scope. Just a heads up


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#25 starbob1

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Posted 10 April 2020 - 06:57 AM

Looks like a good deal ' I say not. $700 for a 10in scope. You can get the Apertura 10in for $559. High Point shipped my 10in in 2 days.


Edited by starbob1, 10 April 2020 - 06:58 AM.



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