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Orion SkyQuest XT6 vs XT8 beginner questions

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#26 Tony Flanders

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Posted 10 April 2020 - 06:23 AM

Here's the bottom line. The views provided by an 8-inch scope are quite obviously brighter and more detailed than the views through a 6-inch scope, but a 6-incher is still definitely in the big-time, especially when used under dark skies. How different are they? There's no way to put the answer into words; you really have to see for yourself.

 

In my opinion, the difference is most obvious when viewing globular clusters and least obvious for the Moon and planets. Incidentally, light pollution affects the Moon and planets not at all; there's no need to travel anywhere to view them. But the massive light pollution of a major city like Salt Lake will wreak havoc on your views of nebulae and galaxies.

 

A good way to assess your light pollution is to step outside on a summer or early fall evening, when the bright part of the Milky Way is high in the sky. If you can't see the Milky Way immediately, you have significant light pollution. If you can't see it at all even after letting your eyes dark-adapt, you have very heavy light pollution.

 

As for disadvantages, they are few. An 8-incher is a bit heavier and costlier than a 6-incher, but neither should matter much unless you're right at the edge of what you can carry or afford. Most adult males can carry either one with little effort.

 

Collimation is distinctly more forgiving with a 6-inch f/8 than an 8-inch f/6; the likelihood of getting near-optimal views as shipped, before you collimate it at all, is much higher. But an 8-inch f/6 is still quite easy to collimate once you've learned the skill. Mostly, you're likely just to check the collimation and find that you don't need to adjust anything.


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#27 Ethan2102

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Posted 10 April 2020 - 12:29 PM

Thanks for all the advice and knowledge you've shared I appreciate it. 

 

After considering what all you guys have said and what I feel is best I think I'm going to go with the 8". Ultimately I don't think the extra weight will be an issue and I'm willing to save up a little extra to get a better scope. I also know that shortly I have won't have much extra money to spend because I'll be starting college soon and won't have another opportunity to buy one for a long time so I feel better about getting the nicer scope. Thanks again for all the help. I'll let you know how it goes once I make the purchase.


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#28 MellonLake

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Posted 10 April 2020 - 01:53 PM

FYI The mirror on the 6" is about 28 square inches.  The mirror on the 8 in. is about 50 square inches.  Thus the 8" has almost twice the light gathering power of the 6".   Going from 6" to 8" seems like a small difference but it is a big difference in the eyepiece, especially for DSOs.  Given the 8" has a 2 in. focuser, if the $ allow, the 8" is by far the better option.  Your decision to go with the 8" is a sound one.  


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#29 LDW47

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Posted 10 April 2020 - 02:21 PM

Thanks for all the advice and knowledge you've shared I appreciate it. 

 

After considering what all you guys have said and what I feel is best I think I'm going to go with the 8". Ultimately I don't think the extra weight will be an issue and I'm willing to save up a little extra to get a better scope. I also know that shortly I have won't have much extra money to spend because I'll be starting college soon and won't have another opportunity to buy one for a long time so I feel better about getting the nicer scope. Thanks again for all the help. I'll let you know how it goes once I make the purchase.

So now that your decision on size is made exactly which brand and model are you going with ? Clear capable skiys !



#30 Ethan2102

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Posted 10 April 2020 - 04:13 PM

Right now I'm comparing the Orion (which is probably my first choice due to price) to the Zhummel, Apertura, and Skywatcher 8" dobs. The Orion seems to be the best one for my budget, but would be open to another model if I can find one of similar price. Any recommendations on the best places to shop?



#31 dusty99

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Posted 10 April 2020 - 04:37 PM

You can start with our host, astronomics:

https://www.astronom...er_aperture=410

 

If you absolutely want an XT8 I've had good experiences with OPT: https://optcorp.com/..._aperture:8:8.9

and High Point (although HP seems low on 8" Dobs at the moment): https://www.highpoin..._type:dobsonian

 

 

 

Right now I'm comparing the Orion (which is probably my first choice due to price) to the Zhummel, Apertura, and Skywatcher 8" dobs. The Orion seems to be the best one for my budget, but would be open to another model if I can find one of similar price. Any recommendations on the best places to shop?


Edited by dusty99, 10 April 2020 - 04:38 PM.


#32 MellonLake

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Posted 10 April 2020 - 06:25 PM

All are likely to be equal in visual quality.  I have an XT10 and love it, the XT8 would be a good choice. However, the Apertura and Zhumell come with better accessories that will benefit you in the long run.   On a budget, I personally would lean towards the Apertura or Zhumell.  Dual speed focuser, Right Angle finder, two eyepieces including a 2in 30mm, laser collimator, cooling fan (these are all nice additions).  FYI since I got my XT10 a year ago I have added all these to my kit and spent way way more than the difference in price between the Orion and the Apertura/Zhumell.  Just my $0.02. 

 

   

 

Rob   


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#33 Cunningr

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Posted 12 April 2020 - 10:58 AM

Hi I am new to this forum, went through same thing you are going through. In the end I bought an XT10I, decided go big or go home.  I really enjoy the scope, but a little bulky for storage.  I think in the long run you might be glad you spent the extra cash for a 8”.  Once you have a the 6” you cant make bigger with out selling it and reinvesting.  I suggest a laser collimating tool makes it much easier to set the mirror up. 



#34 Prima Luna

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Posted 13 April 2020 - 02:02 AM

I don't think anyone's mentioned that you will get more useable power with the larger scope.  Great for planets and the moon.

 

I copied this from somewhere:

 

" The theoretical limit of useful magnification for a telescope is 50 or 60 times the telescope's aperture in inches, or two times the aperture in millimeters"

 

So

6 inch = 300X

8 inch = 400X

 

Keep in mind, these number are under perfect seeing conditions.

 

Link where I got that:

https://www.telescop...ion/p/99813.uts

 

Also, on a DOB mount telescope, I'd rather have the taller 8".

With a smaller one, aiming at objects kinda low might result in having scope's EP lower, making it more awkward to squat down to view through.



#35 SteveG

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Posted 13 April 2020 - 12:38 PM

I don't think anyone's mentioned that you will get more useable power with the larger scope.  Great for planets and the moon.

 

I copied this from somewhere:

 

" The theoretical limit of useful magnification for a telescope is 50 or 60 times the telescope's aperture in inches, or two times the aperture in millimeters"

 

So

6 inch = 300X

8 inch = 400X

 

Keep in mind, these number are under perfect seeing conditions.

 

Link where I got that:

https://www.telescop...ion/p/99813.uts

 

Also, on a DOB mount telescope, I'd rather have the taller 8".

With a smaller one, aiming at objects kinda low might result in having scope's EP lower, making it more awkward to squat down to view through.

FYI, they are the same height. And regarding magnification, it is a rare night that I can use 250x with my 10” f5 scope. Don’t get hung up on magnification! Most of you best and most frequent viewing will be done at 50-150x.


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#36 Ethan2102

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Posted 13 April 2020 - 12:43 PM

After some more research, I've decided to go with the Zhummel Z8. I will hopefully be ordering one shortly! Thanks for all the help.


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#37 Prima Luna

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Posted 13 April 2020 - 07:51 PM

FYI, they are the same height. And regarding magnification, it is a rare night that I can use 250x with my 10” f5 scope. Don’t get hung up on magnification! Most of you best and most frequent viewing will be done at 50-150x.

That's why I used the words "might", " perfect seeing conditions" and " for planets and the moon"! :)



#38 Prima Luna

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Posted 13 April 2020 - 07:51 PM

After some more research, I've decided to go with the Zhummel Z8. I will hopefully be ordering one shortly! Thanks for all the help.

 

Great choice!



#39 Papadude

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Posted 13 April 2020 - 08:53 PM

Following this !

 

The 8" dob is on my upgrade list, so keep us updated after you get it. waytogo.gif



#40 Ethan2102

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Posted 17 April 2020 - 08:32 AM

So there ended up being a change of plans. On Tuesday I was able to purchase an Orion XT8 with a telescope and accessory case for only $150! Unfortunately that night it was super cloudy and the finder scope needed to be aligned and the mirrors collimated. I ended up doing that the next day, hoping the sky would clear. And once again the sky was super cloudy. frown.gif

 

The sky partially cleared last night, but I wasn't able to see much. I ended up waking up at 5:00 am, unsure if I would be able to see anything. But when i woke up the sky was clear and was easily able and was able to observe Jupiter and the Galilean moons, Saturn and Titan, and Mars. Right as the sky was getting light, I was able to observe the moon as it came over the mountains. I can’t wait to get out again.  The weight and size isn't much of an issue at all, though I don't think I would want a larger scope for my first one. Thanks again for all the help, I’m glad I went with the 8”


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#41 Myk Rian

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Posted 17 April 2020 - 10:30 AM

For those of you that have used both how significant is the difference when viewing the Messier objects? That sort of seems to be the hinge point right now, as I'd be willing to drive to get dark skies.

I have a 4.5", had a 6", also own an 8" and 13.1"

The 8" is absolutely my favorite, and the one scope I will not part with.



#42 Cunningr

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Posted 17 April 2020 - 11:21 AM

So there ended up being a change of plans. On Tuesday I was able to purchase an Orion XT8 with a telescope and accessory case for only $150! Unfortunately that night it was super cloudy and the finder scope needed to be aligned and the mirrors collimated. I ended up doing that the next day, hoping the sky would clear. And once again the sky was super cloudy. frown.gif

 

The sky partially cleared last night, but I wasn't able to see much. I ended up waking up at 5:00 am, unsure if I would be able to see anything. But when i woke up the sky was clear and was easily able and was able to observe Jupiter and the Galilean moons, Saturn and Titan, and Mars. Right as the sky was getting light, I was able to observe the moon as it came over the mountains. I can’t wait to get out again.  The weight and size isn't much of an issue at all, though I don't think I would want a larger scope for my first one. Thanks again for all the help, I’m glad I went with the 8”

Excellent price, you'll be addicted now!  I live southern Spain, got my scope all ready to go been cloudy here too, for past 2 weeks, and the forecast  shows no break.



#43 kjkrum

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Posted 18 April 2020 - 07:49 PM

If I were buying new I'd have an XT8, no question. I only have an XT6 because I lucked into it for a stupid price.

#44 James1996

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Posted 20 April 2020 - 03:22 PM

So there ended up being a change of plans. On Tuesday I was able to purchase an Orion XT8 with a telescope and accessory case for only $150! Unfortunately that night it was super cloudy and the finder scope needed to be aligned and the mirrors collimated. I ended up doing that the next day, hoping the sky would clear. And once again the sky was super cloudy. frown.gif

 

The sky partially cleared last night, but I wasn't able to see much. I ended up waking up at 5:00 am, unsure if I would be able to see anything. But when i woke up the sky was clear and was easily able and was able to observe Jupiter and the Galilean moons, Saturn and Titan, and Mars. Right as the sky was getting light, I was able to observe the moon as it came over the mountains. I can’t wait to get out again.  The weight and size isn't much of an issue at all, though I don't think I would want a larger scope for my first one. Thanks again for all the help, I’m glad I went with the 8”

That's a excellent deal! Talking from experience you should love that scope.




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