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#1 DarkStar1984

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Posted 27 September 2013 - 08:18 PM

I am interested in upgrading my telescope. I currently own an Orion 8XT. I am trying to decide on whether I should get a larger diameter Dob (same manufacturer) or one with better optics (Discovery or Zambuto optics). I have about $1500.00 to spend.

Thank you for your help!

#2 starcrafter

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Posted 27 September 2013 - 08:34 PM

I'm in practically the exact same boat -- minus the funds for the upgrade! The next step I'm considering is an upgrade to an Apertura 12" dob, with the tweaker's dream package. Picking that up would leave you with some extra $$$ for EPs! :)

#3 kfiscus

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Posted 27 September 2013 - 08:39 PM

We need more info to give you better advice. Will you be transporting it? How far? How fit are you regarding moving a large scope? What size is your vehicle if you're hauling the scope?

#4 DarkStar1984

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Posted 27 September 2013 - 08:45 PM

I plan on using it at home. Moving it from the garage to the outside. I am in pretty good condition and have no problem moving my 8xt around. If I was to go to another location I would put it in a Nissan Frontier pickup truck.

#5 City Kid

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Posted 27 September 2013 - 08:47 PM

My guess is you would notice more of a difference going bigger than you would going "better", depending on how much bigger we're talking about and how good your current mirror is. Unless you ended up with a really bad mirror, a 12" scope with a massed produced mirror will show you more than an 8" mirror with premium optics. It's hard to beat aperture. Having said that, for my own personal tastes I prefer to have premium optics even if it means a slightly smaller scope. I have both 10" and 12.5" scopes with Zambuto mirrors and I can't see myself not having premium optics on any future scopes.

If my choice was between an 8" with a Zambuto mirror and a 10" mass produced mirror I would probably go with the 8". If my choice was between an 8" with a Zambuto mirror and a 12" massed produced mirror I would probably go with the 12".

#6 MrJones

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Posted 27 September 2013 - 08:49 PM

I got a Z12 (same as AD12) and got the mirror refigured by Steve Swayze. That was about $1000 and is working out well for me. I did the tweaking myself. I don't think you can go bigger very easily for $1500. Good luck!

#7 Billytk

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Posted 27 September 2013 - 08:57 PM

I highly recommend this one with the tweakers dream package. Just my 2 cents.

http://www.opticsmar...a-ad12-dobso...

#8 lamplight

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Posted 28 September 2013 - 06:12 AM

I got a Z12 (same as AD12) and got the mirror refigured by Steve Swayze. That was about $1000 and is working out well for me. I did the tweaking myself. I don't think you can go bigger very easily for $1500. Good luck!


Can you describe any particulars this refiguring has improved ? I've considered this down the line at some point.

Dark star , I have a 10" solid tube as it's easier to put in my small car. But, I'm upgrading to a truss dob 12" for the same reason (with better glass). In many ways I like solid tubes better but sometimes you jus want a little more aperture. I'm sure no one knows what I'm talking about :roflmao:

#9 molniyabeer

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Posted 28 September 2013 - 10:36 AM

For my money, I'd take an average large mirror over premium smaller one. For faint fuzzies, you just can't beat the aperture. My 16" Lightbridge may not be premium optics but they're pretty good none the less and the improvement over my 8" or 10" scopes is no contest.

The drawback is the size and weight. Many of the primo scopes put more thought into engineering the rest of the scope so that it's not so heavy or difficult to move. In fact, I'm working with a guy in our club to repackage my optics into a custom-built truss tube to cut the overall weight by half.

#10 dpwoos

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Posted 28 September 2013 - 11:08 AM

In my mind, there is no question that quality trumps aperture. On the other hand, I think that many folks wouldn't know a great mirror if it bit them on the toe, and it always amazes me what even fellow astro club members are unable to see. So, the best way to answer this question is to observe with a lot of folks/scopes (e.g. astro club), and see first hand what is what. One person's "the difference is night and day" is another person's "I see no difference at all". I guess it shouldn't be surprising, given the differences in observing skill and eyesight.

#11 rnc39560

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Posted 28 September 2013 - 01:52 PM

I would go with a 12" dob, and do some major mods and accessories with the remaining $. Like the tweakers dream package or a zhumell with add on's.

#12 backwoody

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Posted 28 September 2013 - 03:00 PM

I am interested in upgrading my telescope. I currently own an Orion 8XT. I am trying to decide on whether I should get a larger diameter Dob (same manufacturer) or one with better optics (Discovery or Zambuto optics). I have about $1500.00 to spend.

Thank you for your help!


Hi 'Darkstar,' I think you'd really enjoy a used truss dob with a premium mirror in the 12-14" range. There are several 'premium' mirror makers, like Zambuto, John Lightholder, and others you know about. Used scopes are often terrific deals - making the choice between aperture and premium optics easier.

You can have both. Shop smart, and good luck,

#13 GeneT

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Posted 28 September 2013 - 03:20 PM

My guess is you would notice more of a difference going bigger than you would going "better", depending on how much bigger we're talking about and how good your current mirror is.


I agree. If you get a 12 inch Dob, you will double the light gathering over your 8. If you buy a 12 inch Dob, you probably will get good optics, with some chance you will get a bad mirror. If you get a badly figured mirror, you could then have it re-figured. If I were doing this, I would just go with premium optics from the get go. A well figured mirror will last a life time, and your children's should you hand it down.

#14 Paco_Grande

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Posted 28 September 2013 - 08:08 PM

If you can up the budget a little bit, you can pickup a older Starmaster 11" w/Zambuto for $1,600-$1,800. A substantial upgrade all the way around. Plus, it's quite portable.

#15 DarkStar1984

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Posted 30 September 2013 - 05:50 AM

Thank you to all that provided me with information and suggestions. I will need to do a little more homework and will you know my selection. Again thank you to a great group and clear skies!

#16 Jon Isaacs

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Posted 30 September 2013 - 07:47 AM

In my mind, there is no question that quality trumps aperture. On the other hand, I think that many folks wouldn't know a great mirror if it bit them on the toe, and it always amazes me what even fellow astro club members are unable to see. So, the best way to answer this question is to observe with a lot of folks/scopes (e.g. astro club), and see first hand what is what. One person's "the difference is night and day" is another person's "I see no difference at all". I guess it shouldn't be surprising, given the differences in observing skill and eyesight.


In my experience, one cannot say simply say that quality trumps aperture. There are too many variables... Example: a perfect 4 inch refractor versus an average 10 inch Dob.. I know that one.

When viewing small, faint objects, galaxies, nebulae, etc, the eye has very poor resolution, the improvement the smaller, better mirror might provide in fine scale contrast just cannot be seen. A decent bigger mirror will out perform a smaller mirror, the brighter image, the more magnified image are needed. A simple test to demonstrate how really poor the eye is at resolving faint details, view the moon through a solar filter... As a deep sky object, the moon through a solar filter is quite bright but the details that one sees without the filter, they cannot be seen..

For objects like the planets and double stars where there is plenty of light and the goal is increasing the fine scale contrast, then a somewhat smaller high quality mirror will most likely provide superior images to that larger mirror. Still.. it does depend on the conditions.

If I had and 8 inch Dob and $1500 to spend on a larger Dobsonian, I would buy used. If one is willing to buy used, if one waits, there are deals to be had. I would then decide whether I was interested primarily in the deep sky or in the solar system and double stars.

If I were interested primarily in the deep sky, I would looking for a larger scope, a used 16 inch Lightbridge is well within the budget. There is a 16 inch Lightbridge on the San Diego Craigslist for $1000. I would keep my eye on the local Craigslist, and carefully watch Astromart.

If I were looking for a scope for planetary viewing, I would look for something in the 10inch-12.5 inch range with quality optics... The size depends also on your local seeing... some places the seeing is generally quite decent, a bigger scope can take advantage of it, some places the seeing is generally quite poor.. a smaller scope that cools more quickly can be a better performer.

Jon Isaacs...

(Photo: 13.1 inch F/5.5 Starsplitter with a Robert Royce full thickness (= slow to cool) mirror.. bought used via Astromart, well within the budget)

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#17 Kevdog

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Posted 30 September 2013 - 10:54 AM

If I were interested primarily in the deep sky, I would looking for a larger scope, a used 16 inch Lightbridge is well within the budget. There is a 16 inch Lightbridge on the San Diego Craigslist for $1000. I would keep my eye on the local Craigslist, and carefully watch Astromart.


I'd second this. I got my first scope new and my second and third scopes used and saved a bundle.

I picked up an 18" Obession for $2900 in excellent condition.

You should be able to find a 14" to 16" for around $1500 or less if you shop around.

Even the CN classifieds have some:

16" Lightbridge for $1600
http://www.cloudynig...ct=87637&sor...

XX12i for $1100
http://www.cloudynig...ct=87218&sor...

12.5" with premium mirror for $1450
http://www.cloudynig...ct=86449&sor...

#18 dpwoos

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Posted 30 September 2013 - 01:03 PM

I am not a big fan of the "if you are not doing planetary observing then you don't need a great optic" argument. While there seems to be some basis to believe it, I remain skeptical of its validity. Even when observing targets that one would think would be unaffected, I have never been impressed with the views through a poor optic. I can't say exactly why that is, and for sure there are folks that I observe with that don't see any difference. However, there are plenty of folks (including those whose observing skills I respect the most) that do. In my case, I can't count the number of times that I am simply unable to find satisfactory focus, and so I know that something isn't right. This is true even on targets that are themselves faint fuzzies. Our club has an 18" Obsession with a questionable mirror, and I have largely given up on observing with it. On the other hand, our club's 14" (boutique mirror that wasn't, and refigured by a club member) is wonderful and good for everything. There is no question that I would forgo the extra aperture and rather observe with the 14", and I am not alone in this.

The other reason why I don't buy this argument is that I don't know anybody who doesn't look at planets, etc. at high power at least some of the time. What a shame to have a scope that performs unsatisfactorily on Jupiter and Saturn, and that doesn't provide knock-your-socks-off views of Mars. Maybe other folks are ok with that, but I wouldn't have it.

#19 Starman1

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Posted 30 September 2013 - 03:06 PM

Look, we all know that premium optics WITH aperture is the way to go.
But, if I were to suggest what would produce a noticeable difference, it would be first the 12" Chinese/Taiwanese scope if bought new.
That wouldn't necessarily be BEST, though.
Best would be a used truss scope in the 12.5-16" size (might be easier to move than a 12" tube dob) for about the same price.
Lots of people move up to larger sizes or sell their dobs as they get involved with astrophotography, so there is a steady stream of them.

#20 Jon Isaacs

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Posted 30 September 2013 - 04:23 PM

I am not a big fan of the "if you are not doing planetary observing then you don't need a great optic" argument. While there seems to be some basis to believe it, I remain skeptical of its validity. Even when observing targets that one would think would be unaffected, I have never been impressed with the views through a poor optic.



If you define a poor optic as one that provides views you are not impressed with, then it is very likely that you will not be impressed with the views. But great scopes can provide unimpressive views, average scopes can provide knock your socks off views.

Myself, I think in terms of decent optics. What I find is a scope with "decent" optics that is properly cooled, properly collimated will provide impressive views of the planets and double stars if the seeing is stable.

When it comes to the deep sky, a larger scope goes deeper but it also shows the defects in the seeing more easily. It is doubtful that my 25 inch has ever fully cooled or that the seeing has been sufficiently stable to show any defects in the mirror. Point it at a globular, it brings them to life, start looking for galaxies, suddenly there are galaxies where there were none in the 16 inches...

And the the planetary views, on a decent night, they are still amazing and show more detail than a 10 or 12 inch scope.

I do recommend viewing the moon through a solar filter, it is a demonstration of just how bad the eye is at resolving faint details. The image at the focal plane, in the exit pupil is still the moon, the details are still there, the eye just cannot see them, its' inherent in the eye.

And Dennis.. this whole thing about some people not seeing the difference...

Any time I look through the eyepiece of a telescope I am impressed.. Whether it's my $40 at Walmart Powerseeker 70 or the TeleVue NP-101... Not every view is picture perfect but that doesn't stop me from enjoying the view. Amateur astronomy is not about getting the most perfect view, it's about enjoying the view, learning, observing.

I don't need perfect optics, in fact, I rather pride myself on the ability to enjoy some essentially perfect telescopes as well as some that have significant flaws and warts... Oh, I can see the difference but I don't let it bother me..

When I look through someone's scope that is not providing the views I think it ought to... I think to myself... "Now there's a scope that needs a little loving and attention. If it were it mine, it would be providing the good views."

Jon

#21 DarkStar1984

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Posted 30 September 2013 - 06:41 PM

You have all given me a lot to think about. Right now I am leaning towards a buying a used telescope in the 12.5 to 14 inch diameter size with good optics. The trussscopes look to be lighter so thatis another consideration. I realize that patience is key because most of the ads that I have seen require local pick up.

For optics, is the gold standard for mirrors Zambuto optics? Are there other optics that any could recommend? I know that even with a quality company some "lemons" are produced.

John, I will look at the moon with a solar filter and try and see what you are talking about. I never thought of doing that.

Thanks again everyone, you have been abig help!

#22 Starman1

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Posted 30 September 2013 - 07:09 PM

You have all given me a lot to think about. Right now I am leaning towards a buying a used telescope in the 12.5 to 14 inch diameter size with good optics. The trussscopes look to be lighter so thatis another consideration. I realize that patience is key because most of the ads that I have seen require local pick up.

For optics, is the gold standard for mirrors Zambuto optics? Are there other optics that any could recommend? I know that even with a quality company some "lemons" are produced.

John, I will look at the moon with a solar filter and try and see what you are talking about. I never thought of doing that.

Thanks again everyone, you have been abig help!

There are many good mirror makers.
You'll find just about every name in this thread: Mirror Makers
And there is none finer than Carl Zambuto, though there may be others who make the same quality.

#23 Achernar

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Posted 30 September 2013 - 08:11 PM

The best argument for buying good optics is that you will not have to re-figure or replace them. A good mirror remains a good mirror. When the seeing is up to it, you will see things with a large telescope that has good optics you wouldn't believe until you see them for yourself.

Taras

#24 Tony Flanders

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Posted 01 October 2013 - 05:35 AM

I know that even with a quality company some "lemons" are produced.


Actually, no. One of the things you get with premium optics is a guarantee of fine optics, since each individual mirror is hand-tested.

For the record, you can also definitely get first-class optics with a mass-market telescope. Don't assume your mirror is bad just because it's cheap! Carl Zambuto once told a story of a guy who shipped him a mass-market mirror to be refigured. Zambuto tested it and shipped it back unchanged, because it already met his very high standards.

What you don't get with mass-market scopes, of course, is that guarantee.

#25 DarkStar1984

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Posted 03 October 2013 - 06:48 AM

Don,

Thank you for the link to the good mirror makers. So much to learn :D






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