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8" or 10" skywatcher


theskipper1961

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Hello Star gazers lounge

My first post-- basically I got into looking up last year when I bought my grandsons a telescope and decided to try it out and the rest as they say is history, I actually find it hard to believe it’s taken me 54 years to appreciate what I have been missing, so my first question, The scope I am using at the minute is a sky watcher 90 on an EQ2 mount which I like and intend to keep.

I have invested in better eye pieces with a view to using these on my next scope.

The celestron luminous 82 deg x7mm and a nice BST 27mm explorer I am pleased with both.

So which scope do I buy the 8”  200p or the 10”  200PX Dobsonion  skywatchers ,  or the Orion xt The price is not the issue physical size is though , how much taller is the 10” compared to the 8” ? the other obvious question I guess is how much more detail can I expect to see with the 10 “ I would love to be able to see some planetary detail something my present scope is not capable of and basically I only really use this with the low power eye piece most of the time .

I look forward to hearing from you

Thanks  Steve .

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Hello Steve welcome to SGL I understand the 10 inch is the same height as the 8 inch but of course the circumference is bigger and it will.be heavier with the larger primary mirror. Either one is a good choice. As Bizbuilder suggests it may be worth trying to see one in the flesh. Best of luck with your choice

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Hi Steve welcome to S G L

They are both very good scopes for observing, I have the 200P EQ5, and I am very happy with it,

which one you choose is your decision, both scopes are big and heavy to move around, so if you

think the weight doesn't matter then go for bigger aperture, as it will grab more light.

Good luck on your choice of scope, but you won't be disappointed with either.

Clear Sky's

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Hi Steve and welcome

I have the 200 dob and find it just about borderline comfortable to pick up and move outside, its not a struggle but I wouldnt want it any heavier. I have mine next to the kitchen double back doors and have to open them both to get through easily, it is possible with one but fighting with the curtain as well is the difficult bit. I only have to pick up and move 5 metres max, decking outside is the same level as my kitchen floor so only the door threshold to clear.

Having said all this the extra girth is definitely appealing and probably worth the extra struggle when you finally get to observe but, if money is not a problem I would really struggle and get a 12" :D

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Welcome to SGL Steve and Clear Skies in '15!

Whichever size Dob you go for I'm sure you'll get fabulous views.  I have a Newt 200P and wouldn't part with it for the world.  I've used 8, 10 and 12" Dobs and it really is true that size matters, but do have a 'play' either at a local society viewing session (there will be plenty of outreach events taking place after the holiday as the "Stargazing Live" season gets under way) or as suggested, at a dealer showroom.  It can be quite a shock if you're opening a box not knowing just big (and heavy) the contents are going to be!   Also consider a reticle type finder (Telrad, Reigel etc) to replace/supplement the finderscope - trying to get a view through a standard finder can require considerable contortion at steep angles with a large Dob.

Paul a.k.a. The BSG

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aperture is NOT a king.That is a myth made up in astro forums.Not always the biggest aperture winsWhat is the king is quality of your instrument and your eye pieces and seeing conditions.

Back to your question,i would suggest to visit either astro shop or astro event where you could see the scopes in flesh before buying something and then getting the realization that it is not what you want.Also keep in mind there is a good second hand market available in likes of classifieds here or UK Astro buy and sell.Obviously fleebay too.

slower scope will be less demanding to your eye pieces,where faster F-ratio will be more demanding,but again,there are plenty of alternatives out there what does not cost you leg and arm.

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Welcome to SGL :)

From what you have said, I would think the Skyliner 200P to be the better choice. It is the same focal length (and physical height) as the 250PX but is easier on the eyepieces and kinder to the back. Not that the 250 is difficult to move about, but it is heavier than the 200 and needs well corrected eyepieces to show it true potential.

The 200P Skyliner will show you loads of detail in the planets and Moon and worthwhile views of many deep sky objects as well. The difference between the two on solar system objects is not that great.

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Dude_with_the_tube......Why suggest this is a myth ?


The size of a telescope’s aperture is more important than magnification alone. The objective [Lens / Mirror ]  is the part of the telescope that collects the light. If you don't collect light, you  have nothing? The more light you collect, the fainter you can see, under the right conditions.


You don't normally  say, I'm going to buy a 260x magnification telescope, You normally would say, I'm after a 10" telescope, because its the aperture were  interested in. The Magnification is second, afforded by the focal lengths of the OTA-EP.

Maybe ' King' is not the best choice of word to describe its importance, but important it is. 


I agree with your statement, "not always the biggest wins"  as no doubt, some smaller Refractors could  possibly give my telescope a run for its money on the Planets, but when buying a newer telescope, were normally upgrading the Aperture,  very unlikely downsizing, unless to big and heavy  to handle?

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@ Charic

1.i didnt mention anything about magnification

2.If you read until the end,i did mention:QUALITY of optics.Badly configured 16" mirror with astigmatism,low quality and accuracy will show you far less then a good quality configured 8" despite 16" being twice the size.Then also consider atmospheric seeing conditions.smaller mirrior/lens will be less affected by that as the big one and you will see more detail as in that big "light bucket".Uk never was the ideal astronomers place due to that and as such you rarely see any real BIG dobs here.There are quite a few but not so many as you see in US for example.

3.If we talk about magnification,then on these rare great nights,a good quality optics will allow you to use much higher magnifications without image degradation then a low quality one.

As such,to sum everything up: not always the biggest one is the best one,seeing conditions will affect the big gun more then smaller aperture,quality wins over quantity.

And yes I actually downsized from 14" to 6".Weight was not the issue,quality of seeing was.

Hope that helps :) 

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If planetary detail is important, the 8" will not disappoint. With my setup I can clearly see such things as the cloud bands and Great Red Spot of Jupiter and even the Cassini division between Saturns rings complete with moons.

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Hi Steve and welcome , I think you have loads of answers and here is another +1 for the 200p. You say money is no problem so start off with the 8" and see how you handle the size. I know for sure that the views will blow you away and lunar and planetary detail is fantastic . Then you can judge how you want to use it and go from there. Lets face it we never just buy one telescope do we :-) .

Happy new year all......

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Hi Steve,

Welcome :)

If there is one constant in the dobsonian universe it is the relentless need for greater aperture ;) I would recommend the 8" f/6 as it will be much more manageable, cheaper, easier to sell on later if you want, and you will have 'no' visible coma with widefield eyepieces. The next logical step up would be a 12" if you get the fever,  whereas a 10" would lead to a logical recommendation of a 14" or 16" which is a whole new ball park of commitment.

Regards

Dannae

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  • 2 weeks later...

Wow so many replies thank you , And I did read them all  I have to confess I was expecting to see replies ping up on my phone hence late reply .

Well I hope I have not done the wrong thing but in the end due to the physical size issue as I do not have a conservatory or anywhere to store the scope outside

I bought my self a nice used Sky watcher skymax maksutov 150mm aperture , which created another problem as I was hoping to use my EQ2 mount !!

So I then purchased a sky watcher sky t2 altazimeth  mount  on the EQ5 tripod ,I am  pleased with this set up I also had the case for the scope and have just orderd a dew shield and the telrad finder scope so all we need now are clear skies .

I hope this scope will keep me satisfied for some time .

Thanks again for all the replies - you never know i might still buy a dob later on .

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  • 9 months later...

I recently got the 250px dob and the views I've had so far have been brilliant. As has already been said it is fairly hefty to lift so I would also recommend trying to see one and try lifting it.

Regards,

Andy.

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