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Discovery 15" or Meade lightbright 16"?

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#1 John Wang

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Posted 18 July 2011 - 07:19 PM

I want to buy a dobsonian. Which one is better, Discovery 15" or Meade lightbright 16"?

#2 UmaDog

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Posted 18 July 2011 - 09:10 PM

Perhaps you should give us a little more information on your requirements and experience?

Although I don't have experience with either scope, I must say that on paper the 15" looks more tempting. Seems easier to transport as it's lighter and more compact. The suggestion is that the optics will be better.

#3 rocco13

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Posted 18 July 2011 - 10:07 PM

I agree with UmaDog regarding the Discovery optics.

If you're looking at a used Discovery, then that would be the way to go, as their wait times for a new one can drag on for months and months, I'm told. There was a recent thread addressing that exact issue, try a search, and it'll give you more info about those notorious wait times and iffy customer service.

(here's the link)...

http://www.cloudynig...5/o/all/fpart/1

Oh, and welcome to Cloudy Nights!

#4 John Wang

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Posted 18 July 2011 - 10:57 PM

Thanks for the suggestion. I care about the optics. For DSO which one is better? 16" seems to be better, but is 15" discovery made better?
Also I care about weight and setup. Which one is easy?

#5 Jon Isaacs

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Posted 19 July 2011 - 07:04 AM

Thanks for the suggestion. I care about the optics. For DSO which one is better? 16" seems to be better, but is 15" discovery made better?
Also I care about weight and setup. Which one is easy?


This is the way I look at it:

The Discovery is built on the original Obsession model, 8 pole truss with furniture grade plywood construction, a Pyrex mirror, large diameter altitude bearings. All the bearings are Teflon-Ebony Star, it is a perfected design and it is a good one, you may have to monkey with it some to get it the way you want it.

The Lightbridge is a commercial scope, it's a good one but if you look around you will see people do modify them quite a bit. The base is particle board, the scope is steel with steel (I believe) truss tubes. The mirror is BK-7 rather than Pyrex...

A 16 inch Lightbridge costs $1850, a 15 inch Discovery cost $3000... one is a great deal, one is a better telescope.

All that said, the difficulty with Discovery seems be delivery times, not only are they long but one cannot expect the scope to be delivered when promised.

Myself, I would keep my eyes open for a used premium Dob on Astromart.

Jon

#6 UmaDog

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Posted 19 July 2011 - 07:37 AM

They will be the same on DSOs. An inch or two here or there doesn't make a great deal of difference. Travelling to darker skies will make vastly more difference than an inch of aperture.

Your second question suggests that you should go to a local club and see some of these scopes in action. That'll be the most informative thing at this point.

#7 jrbarnett

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Posted 19 July 2011 - 12:32 PM

Used 15" Obsession. About the same price as either of those new. A whole 'nother level of mechanical quality.

Regards,

Jim

#8 BluewaterObserva

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Posted 19 July 2011 - 02:53 PM

I vote used 15" Discovery. :)

#9 Jon Isaacs

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Posted 19 July 2011 - 05:22 PM

Used 15" Obsession. About the same price as either of those new. A whole 'nother level of mechanical quality.

Regards,

Jim



I poked around Astromart, 15 inch Obsessions seem to go for around $4000 used...

Jon

#10 BluewaterObserva

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Posted 19 July 2011 - 05:31 PM

16" Starfinder $800 or best right now too. :)

Really the used Discovery scopes are true bargains right now if'n ya ask me.

#11 Doug76

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Posted 19 July 2011 - 07:29 PM

The Lightbridge is a commercial scope, it's a good one but if you look around you will see people do modify them quite a bit. The base is particle board, the scope is steel with steel (I believe) truss tubes. The mirror is BK-7 rather than Pyrex...


The trusses are aluminum.

#12 Alan Kent

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Posted 19 July 2011 - 09:53 PM

FYI there is a used Discovery 15" for sale on AM, for $1400 I believe. Under the impression it's a solid-tube dob, not a truss or a split tube. Saw one a year ago and it seemed huge compared to my 12.5". It is in northern Wisconsin.

Alan

#13 John Wang

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Posted 20 July 2011 - 05:07 PM

16" Starfinder $800 or best right now too. :)

Really the used Discovery scopes are true bargains right now if'n ya ask me.


That's right. A used starfinder is very cheap. But anyone have experience with those used telescopes? Will the mirror coating degrade after 10+ years?

#14 BluewaterObserva

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Posted 20 July 2011 - 05:37 PM

The coatings were about the only decent thing on them. :)

He is selling for about what the optics are worth, a little less in all honesty.

My Starfinder was from an EQ model an it was very good overall, surprisingly.

#15 John Wang

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Posted 20 July 2011 - 06:03 PM

I never bought a used reflector before. Usually what is the lifetime for optics?

#16 BluewaterObserva

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Posted 21 July 2011 - 05:31 AM

No real life time spec. Coatings do get bad. But then again I have seen pritine 50 year old+ mirrors going strong with the original coats on them.

If the optic was used predominantly close to say an ocean? Coatings go down hill much much faster from the salt corrosion in the air.

#17 Achernar

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Posted 21 July 2011 - 07:35 AM

The glass lasts forever, unless they are handled or cleaned in a careless manner. After all, dropping a mirror does nothing to ensure a long life span. After annealing, grinding, polishing and figuring a glass mirror will retain it's precise shape longer than several human lifetimes if not longer. I have a 6-inch with a mirror that is more than 30 years old, and it works as well as the day it was turned on the stars for the first time. The coatings will of course degrade, especially where there is a lot of salt in the air or other corrosive agents such as sulfur dioxide due to air pollution. You can get the coatings replaced without harming to the glass at any coating laboratory, my 6-inch mirror has been re-coated three times over the years without altering it's performance.
With regrards to your original question, I would have to give the nod to the Discovery since the optics are in general good to excellent quality. I bought a 10-inch F/4.5 Discovery Dob used and have been very happy with it ever since.

Taras






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