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Meade 12" Lightbridge, Orion XX12i or Zhumell 12"

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#1 saemark30

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Posted 26 July 2013 - 03:13 PM

Which one would you recommend?
Which has the best optics?
Are there better scopes to consider for the money?
These are $1300 and under.

#2 Starman1

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Posted 26 July 2013 - 03:19 PM

Which one would you recommend?

Meade Lightbridge if you can still get one from a dealer. It's lighter, has a lower center of gravity, and is easier to transport. It comes with a fan and has a decent mirror cell and focuser.

Which has the best optics?

The Zhumell and Meade are from the same maker. The Orion is from a different company. All are about the same.

Are there better scopes to consider for the money?

You didn't mention Apertura, which is also from the same maker as the Meade and Zhumell.

These are $1300 and under.

And definitely the best bang for the bucks.

#3 a__l

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Posted 26 July 2013 - 03:42 PM

"Fresh" Meade 16" Lightbridge, yesterday interferometric test stand. Primary mirror at two radii, the pit edge, a two of zones and dense radial ripples. Astigmatism. Fluffy star.

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#4 saemark30

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Posted 26 July 2013 - 04:10 PM

Oh! That's bad.
What interferometric setup did you use to test it?

#5 a__l

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Posted 26 July 2013 - 07:18 PM

I do not have anything to do with it. A group of independent amateurs astronomers in Moscow ... assistance to other amateurs when buying ...

ps.
PV: 1/1.0
RMS: 1/5.3
Strehl: 0.244

#6 mark379

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Posted 27 July 2013 - 09:40 AM

If you are looking int a Truss scope, go for the Orion. Meade has some balance issues, and the Orion has better build quality, plus computerized object locator.
If its a solid tube, Zhumell is great for the money, but heavy to transport.

#7 Starman1

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Posted 27 July 2013 - 12:22 PM

The Orion "truss" isn't a real truss scope because the mirror bucket is still too large, the poles too short, and the side panels of the rocker box too tall.
This makes transport more difficult, and flex in the side panels of the rocker box more noticeable. It's more of a "split tube" design.

Not that the Meade 12" doesn't have problems of its own. Like the Orion, it could benefit from buttresses on the side panels. But the side panels are significantly shorter and the scope much easier to transport. And, it has a nicer focuser, IMO.

I do like the digital setting circles on the Orion, though the non-standard encoders can sometimes give difficulties. Frankly, though the unit emits way too much light in use, the idea of having a number pad and a hand controller for digital setting circles is brilliant. That alone might tip the scales toward the Orion.

All dobs have balance issues with eyepieces of radically different weights, even the Orions. Increasing the pressure in the bearings is not a solution since it makes the motion of the scope jerkier. The best solution is balance weights, and the innumerable CN threads on counterwights for dobs in general testify to the effectiveness of that solution. [Indeed, some beautifully-machined stainless steel clip-on and bolt-on weights exist for low prices.]

Whichever unit is purchased, make sure to obtain at least one bottom fan for the beast, as this will make a lot of difference in viewing.

#8 mark379

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Posted 27 July 2013 - 01:26 PM

I have had both the Meade and Orion versions and I can attest to the better stability of the Orion. The Meade had flexure while the Orion did not.
The Orion XX dob DOES have buttresses on either side of the base which add stability over earlier designs.
I do agree now that the GSO Dual speed focuser That Meade Utilizes is a little bit nicer.

#9 christheman200

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Posted 27 July 2013 - 05:12 PM

I have the XX12i and I would like to say that the mirror bucket functions perfectly for it's size when transporting unassembled, say to a dark sky site, but it makes it very hard to carry as one unit to your backyard. I can't say much for the object locator as my altitude encoder was busted out of the box and Orion forgot to send the replacement to me for a week... but the motions aren't too bad overall. Side to side movement is a bit jerky but manageable. I find that the focuser does vibrate quite a bit, but it is rather smooth even though it takes more force than I would like to make it budge.

#10 Starman1

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Posted 27 July 2013 - 05:28 PM

I have the XX12i and I would like to say that the mirror bucket functions perfectly for it's size when transporting unassembled, say to a dark sky site, but it makes it very hard to carry as one unit to your backyard. I can't say much for the object locator as my altitude encoder was busted out of the box and Orion forgot to send the replacement to me for a week... but the motions aren't too bad overall. Side to side movement is a bit jerky but manageable. I find that the focuser does vibrate quite a bit, but it is rather smooth even though it takes more force than I would like to make it budge.

Have you loosened the thumb screw below the focuser?
If azimuth force is too high, have you loosened the center bolt?

#11 SteveG

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Posted 27 July 2013 - 05:43 PM

I do not have anything to do with it. A group of independent amateurs astronomers in Moscow ... assistance to other amateurs when buying ...

ps.
PV: 1/1.0
RMS: 1/5.3
Strehl: 0.244


All the Chinese imports have stinkers that get through. I suggest buying when you know you can do a star test, and from a reputable dealer that will exchange the scope in the event of a bad mirror. I have a 10" Lightbridge, which is a very good design with excellent motion. I had my mirror tested:
P-V 1/6.2
Strehl: .959

#12 frito

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Posted 27 July 2013 - 05:51 PM

I've used and fixed my club's 12" lightbridge. it has a few major flaws (or at least older ones do)

the bearing system needs modifications, ball bearing Az bearing are way too smooth and the felt/plastic brake Alt bearing system is clunky. if it was my scope to modifiy i'd do away with both in favor for teflon and ebonystar/FRP bearing surfaces like i have on my XT10 (modified) the Orion XX series scopes already use ebonystar/teflon surfaces, i have used other folks scopes that have them and while not perfect they are better than what the standard lightbridge has.

the 2nd complaint and what I fixed on my club's lightbridge is the mirror cell, the exact part Don says is superior. he can correct me if i'm wrong and they fixed this but at least my club's lightbridge and many that i have read on the internet suffer from an easily fixed issue where the springs in the cell are far too soft to support the mirror making adjustments and holding collimation a very very difficult thing. before i replaced the springs our club scope would dramatically shift in collimation just by using the scope, using the lock screws would result in shifting collimation out very easily so they basically didn't work. after i replaced them and tightened up all the screws on the scope it was much better in performance as far as holding collimation was concerned but still not perfect but thats kind of to be expected for a three truss commercial scope.

cannot comment on the Z12, never used one but if its a solid tube it should be a great scope, i've used Z8's and 10's and they are great.

#13 Starman1

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Posted 27 July 2013 - 06:37 PM

The support for the primary mirror is well done in the LB. The springs are, as you mention, not adequate. It's why Bob's Knobs, Farpoint, and a host of other dealers offer upgrade springs. I would recommend the change. After the change, though, you have a properly-operating mirror cell, and the locking screws no longer have to be used. There are after-market counterweights that screw into the empty holes.

All of these entry-level scopes require some work, whatever brand they may be. That's part of the fun over a period of time.

All assuming the optics are decent, of course.

#14 saemark30

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Posted 27 July 2013 - 07:09 PM

Are the Meade 12" lightbridge still available?
It is backordered on Amazon

#15 frito

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Posted 27 July 2013 - 07:17 PM

The support for the primary mirror is well done in the LB. The springs are, as you mention, not adequate. It's why Bob's Knobs, Farpoint, and a host of other dealers offer upgrade springs. I would recommend the change. After the change, though, you have a properly-operating mirror cell, and the locking screws no longer have to be used. There are after-market counterweights that screw into the empty holes.

All of these entry-level scopes require some work, whatever brand they may be. That's part of the fun over a period of time.

All assuming the optics are decent, of course.


I don't disagree, all entry level commercial dobs can stand for some user made improvements and I also agree its part of the fun. the mirror cell spring issue on the lightbridge is a pretty major problem however and should be known before buying one because it is highly detrametal to the optical performance of the scope, that being said its easily and cheaply fixed, i found suitable replacement springs at orchard supply hardware and while i was at it cleaned the mirror and had it back together repaired in less than two hours, the silicon mounting job they do on the mirror should however be noted, its not easy to get the mirror out of the cell on it, i put it back in using cork to support it, much better than silicon in my opinion. the cell design support wise is good for a commercial scope but the metal reinforced plastic triangles can and will crack over time so its by no means a high end mirror cell but it is better than you often see on commercial newtonians.

#16 SteveG

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Posted 28 July 2013 - 08:50 PM

I've replaced the primary support springs on every commercial dob I've purchased.






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