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  1. #1
    enigma_0Z's Avatar
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    Default Orion vs. Meade vs. Zhumell vs. Skywatcher....



    I'm pretty sure that I want either an 8" or 10" dob, but I'm not sure which is the best... All four companies make one, and each says that it's the best of them... So, aperture aside, which is the best scope?

    Points of interest...

    Zhumell scopes come w/ laser collimators. Orion scopes come w/ Colilimating caps. Others, unknown.

    The Sky Watcher and Meade both come in a truss design (portability isn't that much of a concern, however).

    The Sky Watcher and Zhumell both come with two EP's. Both accept 2" EP's, but the Sky Watcher only comes with 1.25" ones. The Zhumell comes with a 2" 30mm (40x) and a 1.25" 9mm (133x). The Sky Watcher comes with a 1.25" 25mm (48x) and a 1.25" 10mm (120x)

    The Meade and Orion come with only one EP. The Orion's a "Sirius Plossl" 25mm (48x), and the Meade's a 26mm (39x)

    It seems that all of the scopes come with a wide angle EP appropriate for their aperature (between 40 and 48x), and it also looks like the 133x may be good for viewing the moon, planets, etc...

    All come with a "Crayford" style focuser...

    They all come with a different finder...
    • Meade: "Red dot" finder
    • Zhumell: 8x50 finderscope
    • Orion: reflex scope
    • Sky Watcher: 8x50 right-angle viewfinder


    It seems like the Sky Watcher may be the least "good" of the bunch, but I'm not a telescope expert and have never used any of these...

    So, I guess I have some questions...

    • What's a Sirius Plossl?
    • What's a Crayford focuser?
    • What is a "Red Dot" finder?
    • What's a Reflex Scope?
    • What is a right-angle finder?
    • Is it worth purchasing a scope that comes w/ two EP's?
    • Does 2" vs. 1.25" matter with an EP?
    • Is the laser collimator worth it?
    • How would I collimate the scopes that don't come with a collimation aid?
    • Most importantly, which company produces the best optics?

  2. #2
    misterdanny's Avatar
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    I can't answer all of your questons, but I can answer some...

    -finderscopes.... a red dot scope and a reflex scope are actually the same thing, it's kind of a tamayto/tomahto thing... You might most often see these things mounted on guns for aiming. (on guns they are usualyl called sights and not scopes though, but they are essentially the same thing). Look on google images for "reflex sight" if you still don't know what I'm talking about.

    With my experience with telescopes (which has only been a few times, but I think I have experience enough to give some input) I have found that "non magnified" (ie red dot/reflex scopes) are the best. I find it very difficult to come in on things with a magnified finder. However you may not have the same issue, and a magnified finder may help you locate bearings with stars that aren't visible with the naked eye.

    A right-angle finder would be useful for releaving neck and back pain, as you won't have to get down at the end of the telescope to look through it (the finder scope). I haven't used a right angle before, but I've heard it makes locating things harder since your not facing he direction of your target. So I guess it might be a tradeoff between comfort and finding stuff. However you may want to try one out for yourself instead of accepting my hearsay.

    Having two EPs from the start sounds like a great way to get started, however you might want to buy your own seperate EPs, and the ones that came with the scope may end up unused. (not to say the ones that come with the scope will be unsatisfactory, you will probbaly use it/them for a long time). I can't speak much on the differnce between 2" vs 1.25". From the sounds of it the 2" would be better, as it would make sense that you would have a larger field of view, personally I can't pick out much of a difference, but maybe a more experienced observer can.

    I've only collimated a scope once, and I'm still not sure how well I did. (was able to see things though, so I guess that is good). I might end up getting a laser collimator with my scope that I just bought (which is supposed to come today!), but I wanted to take a few whacks at it without a laser first.

    Unfortunately I can't say too much about your other question, I don't feel experiences enough to give you an adequite response. I will say that I've noticed almost all scopes come with a crayford focuser, so even if you knew what it was.. you would probably buy it anyways.

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  4. #3
    TambourineMan's Avatar
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    I'll take a stab at some of these, but I am a noobie. Hopefully if i tell you something that is incorrect, other more experienced members will correct:

    1. A possl is a type (design) of eyepiece. I think Sirius is just one of Orions series of EP's - Manufactures have different series at different price levels. goi here for EP designs:

    Eyepieces

    2. A Crayford focuser is a type of focuser that is smoother than a rack and pinion.

    3. "Red Dot" finder, reflex scope, and right-angle finder: misterdanny already answered.

    4. Are the included EP's any good. Well, you need some to start. I have read that the Zhumell ones are considered a cut above the others. You can buy used EP's on Astromart for as little as $15 delivered. With EP's you generally get what you pay for and some go for many 100's of dollars.

    5. Does 2" v 1.25" inch matter. You can't use a 2" in a 1.25" holder (focuser), but you can use a 1.25" in a 2" (with an adapter). Some EP's are dual 2" and 1.25." I think 2" EP's are more expensive especially in higher magnifications.

    6. Laser collimators make it much easier to collimate in the dark. Initially and usually infrequently you also need a cheshire/sight tube one to check the secondary mirror. Once aligned the secondary usually doesn't need to be aligned every time. With a truss tube design you will probably need to align the primary mirror everytime. For a solid tube, if the scope is handled gently you may not need to do it every time. There have been some problems with some laser collimators. I recommend a Hotech SCA (Sky & Telescope's product of the year for 2009). Others swear by the Howie Glatter (but it's expensive).

    7. You will need some sort of collimator to at least get things roughly collimated. Once it's close, every collimation should be checked by a star test. You can make a crude collimation tool out of an old 35mm photo film cannister by carefully drilling a hole in the center of the cap and cutting the cannister part in approximately half to make a tube that will fit in the 1.25" EP holder in the focuser.

    8. That's the 64,000 dollar question. I'll leave it to more experienced members.

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  6. #4
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    Default

    hey,

    i think a plossl is like a 4-5 element eyepiece. and i think Zhummel or Skywatcher would be good. not accusing orion of anything but the zhummel comes with better eyepeices. the only thing is that zhummel is a solid tube. if portibilty is problem i would recommend getting a 8 inch solid tube, or getting a 10 inch truss tube ( a little more $$$) skywatcher or meade. it is possible to get 10 moved, but its kinda hard.

    Celestron

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    Default

    the zhumell seems like the best deal, from what i've seen. the orion uses springs on the base to provide tension on the scope, and i've read so-so things about that. oh and the meade looks the coolest.

  8. #6
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    Default

    What's a Sirius Plossl?
    A Plossl is a type of EP of 4 elements named after its designer, Georg Plossl. Sirius is a house brand.

    What's a Crayford focuser?
    A crayford is a focuser design that works by friction as opposed to gears, and so has no backlash

    What is a "Red Dot" finder?
    A type of Reflex finder

    What's a Reflex Scope?
    A finder that doesn't magnify. but projects a reticle like a red dot or a cross hair or concentric rigs onto a window. Many are in fact rifle sights adapted for telescope use

    What is a right-angle finder?
    A magnifying finder where you look in at right angles rather than a "Straight Through" where you look in from behind

    Is it worth purchasing a scope that comes w/ two EP's?
    Yes definitely. You will ultimately want more than two EPs anyhow.

    Does 2" vs. 1.25" matter with an EP?
    No not really, leastwise not at entry level. 2" becomes an advantage for long FL EPs and for the high end exotics but for a first scope on a budget its no. Having a 2" focuser available is probably a good idea for future expansion of you EP collection

    Is the laser collimator worth it?
    Thats one for individual opinion. My opinion is no, as the laser itself needs collimation, others swear by them. A "Cheshire" type is as good as any but really this is pure opinion

    How would I collimate the scopes that don't come with a collimation aid?
    You can collimate directly from a star but this method would usually only be used for fine tuning. Better to get a collimating tool

    Most importantly, which company produces the best optics?
    Of the four you list, Orion and Skywatcher are both from the same manufacturer (Synta). I'm not sure who makes the Meade dobs, could be Meade themselves, or could be subbed out. The Zhummell is made by GSO.

    In the current models available Synta has higher quality optical coatings than the GSO offerings. Can't comment on the Meade in their current offerings

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  10. #7
    enigma_0Z's Avatar
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    Quote Originally Posted by Vinnie View Post
    A Plossl is a type of EP of 4 elements named after its designer, Georg Plossl. Sirius is a house brand.



    A crayford is a focuser design that works by friction as opposed to gears, and so has no backlash



    A type of Reflex finder



    A finder that doesn't magnify. but projects a reticle like a red dot or a cross hair or concentric rigs onto a window. Many are in fact rifle sights adapted for telescope use



    A magnifying finder where you look in at right angles rather than a "Straight Through" where you look in from behind



    Yes definitely. You will ultimately want more than two EPs anyhow.



    No not really, leastwise not at entry level. 2" becomes an advantage for long FL EPs and for the high end exotics but for a first scope on a budget its no. Having a 2" focuser available is probably a good idea for future expansion of you EP collection



    Thats one for individual opinion. My opinion is no, as the laser itself needs collimation, others swear by them. A "Cheshire" type is as good as any but really this is pure opinion



    You can collimate directly from a star but this method would usually only be used for fine tuning. Better to get a collimating tool



    Of the four you list, Orion and Skywatcher are both from the same manufacturer (Synta). I'm not sure who makes the Meade dobs, could be Meade themselves, or could be subbed out. The Zhummell is made by GSO.

    In the current models available Synta has higher quality optical coatings than the GSO offerings. Can't comment on the Meade in their current offerings
    Thanks again for all the detailed and informative responses, yet information leads to more questions....

    What makes coatings inferior? How would an inferior coating on a lens/mirror affect a view? Do inferior coatings just not last as long?

    Does the lower quality coatings on the Zhumell (GSO) explain why it's less money than the equivalent package when purchasing an Orion scope and all the goodies that come with the Zhumell? I personally trust my own eyes (as imperfect as they are...) anyway, and with the issues that I've heard about the laser collimators, makes me wonder how effective they are... For reference, I don't tune my guitar with a tuner, but with another instrument that is in tune, btw.

    Anyway, I'm digressing. An equivilent package from Orion direct is about $500 incl. shipping vs. just under $400... That package is the scope (w/ the 25mm Plössl), a 10mm Plössl, and a Cheshire collimator. I still want a solar and lunar filter, but those may come later. Doesn't include the cooling fan for the primary mirror or the free green laser, but those almost seem frivolous to me anyway. Do inferior optics account for the $100 difference?

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    What makes coatings inferior? How would an inferior coating on a lens/mirror affect a view? Do inferior coatings just not last as long?

    Does the lower quality coatings on the Zhumell (GSO) explain why it's less money than the equivalent package when purchasing an Orion scope and all the goodies that come with the Zhumell? I personally trust my own eyes (as imperfect as they are...) anyway, and with the issues that I've heard about the laser collimators, makes me wonder how effective they are... For reference, I don't tune my guitar with a tuner, but with another instrument that is in tune, btw.

    Anyway, I'm digressing. An equivilent package from Orion direct is about $500 incl. shipping vs. just under $400... That package is the scope (w/ the 25mm Plössl), a 10mm Plössl, and a Cheshire collimator. I still want a solar and lunar filter, but those may come later. Doesn't include the cooling fan for the primary mirror or the free green laser, but those almost seem frivolous to me anyway. Do inferior optics account for the $100 difference?
    OK, well to play with semantics, I'm not sure that "inferior" is the right word as this implies sub standard which is not the case. GSO mirrors are of a high standard. Synta Mirrors are of a higher standard

    To attempt to quantify this, the higher the standard of a mirror, the less light dispersion and the more light gets to the EP. The term "Dispersion limited" as quoted by suppliers simply means that a mirror is more than 80% reflective. Also a higher quality coating will have a longer lifespan, but we really are talking a very long time before mirror degradation becomes an issue. How long? well that depends on how it is cared for, or in this case not cared for as overzealous cleaning can lead to a shortened mirror life. Lets say 10 years min to 20 years max for a reasonable mirror

    At the EP I believe there is a difference but it is subtle, and there are thousands of happy GSO owners out there, just for mine I would pay the extra for the Synta, which then again becomes a personal opinion.

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  13. #9
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    I wouldn't get too excited about the collimation cap included with an Orion. It is essentially the same as the 35mm film canister I mentioned above, although it does have a grided reflective surface on the inner side of the cap which can help align things. It is definitely something you would have to in do during daylight or with lighting. The advantage of the laser is that it can be done when its dark.

    The laser collimators can be a problem. When I bought my used scope I was concerned because the seller collimated it for me with his and instead of a round red return beam it was a long red line that ran from one edge of the 45* screen to the other with a brighter spot. People told it was no problem witht he telescope, but rather with his laser. Later someone else collimated it with his laser before I got my own and it showed the bright red return spot so they were correct. I wish I had studied more about collimation before i bought my scope.

    Lasers themselves have to be collimated especially when you first get them. Neither they nor telescopes seem to always come aligned straight from the factory. I got one that because of its design is said not to have the problems that other laser collimators have. apparently one way to improve on the perfomance of some laser collimators is to use them in conjunction with a barlow which is what the seller said he usually did - he just didn't use that procedure when showing me how to collimate it

    You really can only use a laser collimator for the primary mirror. To get the secondary (diagonal) centered on the primary and tilted properly you need a good cheshire collimator and sight tube. The secondary mirror has to be done in good lighting but fortunately does not have to be done that often - others tell me once or twice year at most.

    But collimating the primary mirror has to be done more often - with a truss one probably after every time you set it up. Without a laser collimator you need bright lighting to collimate and if you are observing with a group, this would be a no no. The alternative is to set up in place during daylight which is not a bad idea as the mirror has to have time to cool down anyway. you just have to plan ahead: set up, go have supper and a beer and come back and do some star gazing.

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    I can add this little bit of knowledge . The 8in will have a mirror surface area of 50.265 sq. inches and the 10in. will have a mirror surface area of 78.539 sq. inches ...and a 12in will have a surface of 113.097 sq. inches of surface area .. Quite a difference with just a small increase of mirror size .
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