Skywatcher vs bintel vs guan sheng newtonians

[Steampunk]

Hi all,

I've been looking at the Newtonian reflectors, mainly the 200/1000. But I've come across a few and I don't know how they compare to each other.
Mainly it's the skywatcher 200/1000 vs the bintel 200/1000 vs guan sheng 200/1000. Price and mount aside (just OTAs) which one is better? I will be going into astrophotography if that helps...

Cheers in advance

Scott

[Amaranthus]

Some are carbon fibre tubes, some steel. The former is lighter and has better thermal stability. They also differ in the quality of the focuser.

[glend]

I have the GSO 8" f5 1000mm fl newtonian that I use for astrophotography. It's a good scope for astrophotography, GSO mirrors have an excellent reputation, and has the 10:1 fine tuning focuser with ability to lock the tube in place, and my dslr easily achieves focus and it can be used visually with my entire ep range when combined with the supplied 35mm extension. The scope includes a low vibration primary fan at the rear and it doesn't cause any noticable image issues even if run during 5min subs. It is an excellent scope in terms of value for money. The Bintel scope is identcal except for the sticker on it. The steel tube GSO is not a heavy scope and at this size range carbon fibre doesn't save much, if any, weight but there would be a substantial price difference. I can easily lift mine onto my NEQ6 mount., and I'm 65 with a bad back. I have a ZWO guidescope and ASI130 camera sitting on top of mine and have no problems with flex.

Btw mine is for sale in the classified ads here, only four months old - I am very happy with it but I need to sell it as I am building a 10" newt and need the space.

Talk to Luke at Andrews Comms for all the details on these scopes, and ask Luke which dovetail they are shipping with them these days.

[dannat]

bintel & GSO are same factory in taiwan, skywatcher is chinese [synta]
essentially at this price point machine made mirror should meet a certain standard -can be luck if you get a good/bad one
things you should look for as extras to seal the deal:
-focuser, does it have 2:1, 10:1
-does the tube come with an extension tube - meaning it will reach focus with your camera straight away [& not have to have mirror shifted up the tube]
-what kind of screws are on the secondary/primary adjustments -the more screws you can adjust tool-less the better
-will someone throw rings into the deal as part of pkg/cheaply

[mental4astro]

I'll start this way by sharing who makes (for their own brands and others) and owns what:

GSO, makes instruments for GSO and Bintel. Same gear, just Bintel pays for their label to be put onto the gear. Like Daniel said, made in Taiwan.

Synta, owns the following brands Celestron, Skywatcher, Tasco, Jason, Konus, Saxon, and a few others. They make their gear in China.

Both also outsource to other companies the production of some components.

While most people would think that there is little difference between the two, there actually is optical wise, which is more noticeable with the larger apertures.

When I was looking for a line of optics to offer directly through Gondwana Telescopes, I did not want to offer just 'good' optics. The investment in one of my scopes is a substantial one, so my criteria for optics had to be a 'better' quality. And there is no way around it, quality costs money.

So how does this relate to GSO vs Synta (Skywatcher)? Simple. While the first difference is price, Skywatcher optics are more expensive than GSO, there is a visual difference. I have looked through dozens of GSO and Skywatcher scopes, and the difference is always the same. The final polish of Skywatcher is time and again superior to GSO. You see this by doing a side by side comparison. Looking at the same object, at the same time, the image in the Skywatcher has significantly LESS scatter than the GSO. Black is black, not 'fuzzy grey'. Stars are sharper, and focusing is more positive as a result.

The price difference reflects this. To get the quality of image this good it takes longer, uses more materials, and has higher labour costs. And there is no way around this.

Now, the with the rest of the hardware, there are differences, and the pros and cons are pretty much evenly shared. Remember, these components are built first on price and speed of production. Quality is the compromise. This is why the after market is so large for focusers, spiders, mounts, eyepieces, mirror cells and so on. And even for optics, there are better quality primary and secondary mirrors, and they all cost more for the same reasons - it costs more to produce.

Carbon fibre tube vs steel tube? On the most part there is no overwhelming difference. Closed tube systems have other problems that as far as I can determine negates any difference between the two. Offering a CF tube is more of a marketing ploy than a thermo dynamic one. To argue that there is a weight difference is a mute one when you are dealing with the carrying capacity of mounts (if you are serious about imaging), the weight difference between a CF tube over a steel one is small percentages across the entire weight of the whole rig. If you are counting these percentages, you are going too light in your mount. You need to understand the way heat works in a closed system to justify one over the other, and then you still need to deal with the thermal problems. Open tube systems do not have the same issues. They have issues, yes, but half those of closed systems, and again less if the instrument is a visual one vs photographic.

Now, GSO or Skywatcher? For overall optical quality, Skywatcher has it between the two.

[Marios]

What mount do you have?

[glend]

Keep in mind that the issue of mirror quality as expressed by Mental4Astro are subjective at best in visual use by a well trained visual observer, however, it is less important in imaging. In imaging you are after presentation of the field to the camera sensor, as a fully(100%) illuminated field. I recently ran a thread that discussed the importance of mirror quality in imaging scopes ( as a precursor to my 10" scope build and mirror choice); the consensus among experienced imagers was that the investment in say a Zambuto mirror was wasted money in an imaging scope, in fact the 1/12 wave finish of the GSO mirror was more than adequate for imaging. There is no doubt that coating reflectivity is higher in the expensive mirrors but this is simply equated in the field by a slightly longer exposure to get the same light ( and I'm talking just a few seconds difference). If your objective is to use the 8" newt where it works best - wide-field DSO photography then the GSO mirror is more than adequate. If you plan on using a DSLR, and are thus constrained by the sensor and pixel size available in those cameras, then the GSO mirror will be fine. There are plenty of very good astrophotograhers on IIS using the GSO truss tube RC scopes, which use the same quality mirror making technology as the 8" newt. Have a look at posted images from GSO scopes and don't be swayed by visual proponent arguments that can be irrelevant to imagers.

Have a read through the thread linked below on imaging mirror quality, paying attention to Clive Milne's comments:

"At typical focal ratios, the focal plane is sufficiently under sampled by any ccd that you are likely to encounter that there is no noticeable improvement to be gained by a mirror more accurate than 1/3 wave.
GSO mirrors are typically much better than that so are as good as you need...... "

http://www.iceinspace.com.au/forum/showthread.php?t=124907&highlight=imaging+mirror

Of course, like most threads about mirrors, the usual suspects appear to offer their pronouncements, but even Satchmo has to concede there was little to be gained.

[mental4astro]

Hi Glen,

My talk of the polish quality has nothing to do with figure. The best analogy I can thnk of is looking through a window. The glass won't be optically flat - we know this & can see this, but it is nice and clear. Now take another window & take to it with fine emery paper. The figure on each is as poor as the other, but one is clear, the other dull and frosty. This is the difference I am talking about, and this does make a difference in imagining. You rather a highly polished lens or a frosty one? Scatter will affect your image quality.

Your argument on figure is valid. Never disputed that. I actually agree on the most part. I ask not to confuse figure with finish.

[doppler]

:thumbsup: for the skywatcher. I have a 10" 1200mm skywatcher dob with tube rings fitted and mounted to a eq pier. The optics are excellent and the mirror is factory set for camera (prime) focus. I also have an older 10" f4.5 meade starfinder, but the optics are no where near as good as the skywatcher.

As for steel tubes v/s carbon, I have an old 8" f6 newt with a fibre glass tube and it does not have the half the dew problems that I get with the 10" steel tube.

Rick

[rustigsmed]

I have a bintel (gso) and a skywatcher 12" reflector, I find the skywatcher to be of a higher quality. particularly in terms of having a sturdier spider vane (bends very easily on bintel not so much on skywatcher) and better collimation springs (didn't need replacing on skywatcher but did on bintel). This is the black diamond skywatcher it may not be the case on the standard model skywatcher.

[Shiraz]

fwiw, I have a 200f4 GSO, a 250f4 Skywatcher CF and a 300f5 GSO. All have much better resolution than the atmosphere for DSO imaging and the two GSO scopes also do a good job of high res lucky imaging (haven't tried the SW in this role).

For visual use, the Skywatcher is possibly slightly ahead on contrast, but the 200f4 GSO has slightly better figure. For imaging, they are all way better than required - if you are concerned that the contrast might be a slight bit lower on a GSO due to slightly rougher surface, just boost it in software - imaging lets you easily correct things that could be a problem with visual.

CF is great for thermal stability. For DSO imaging, I typically have to refocus my steel tube scopes every 15 minutes or so, but the CF can stay in the zone for maybe an hour on a good night.

Mechanically, the SW CF is better made than the two GSOs - but so it should be, it cost more than the other two put together.

[DavidU]

I found the same as Mental4astro did regarding GSO and Synta. I have a very nice 12" Synta mirror, great optic. I would say the coating and SiO overcoating is a little better with the Synta as well.

[Steampunk]

Wow cheers for the input guys, i really appreciate it.

Thanks glend for the link to that thread it was good read and interesting to see people's point of view of mirrors used for imaging.

So really skywatcher has generally better quality build, whereas GSO is a little bit less, hence the price difference. Mirror quality is still a little bit debatable.

I don't think I can justify a cf, I'm pushing the budget (and the mrs) as it is.

I've been looking at Andrews website at the black diamond 200/1000 with the neq6pro. I was undecided on either the heq5pro or the neq6pro but from what I can gather I would be better of with the neq6pro in the long run.

Cheers again everyone for the great info! Glad I signed up to the forum :D

[Amaranthus]

Scott, if you are going for an NEQ6 then consider pushing the wife... Errr... budget a tad further and get an AZ-EQ6. It has a smooth belt drive, and in Alt-Az mode it is great for visual too...

[glend]

I use an NEQ6 and can recommemnd it and it gives you the imaging load capacity to go abit bigger. Re the AltAz version, they are a nice nice bit of gear but if your pure imaging its overkill in my opinion. There are belt kits for NEQ6 but honestly I can't see the need as my longest subs show no issues. With the mount its important that you don't put more imaging load on it than maybe 2/3s od its rated visual capacity.

[Steampunk]

Cheers guys. Yeah going the with the Az eq6 mount would blow the budget to much.

Just gotta wait until after Xmas to get the equipment now.

[inertia8]

Sorry to but in here, but does anyone know how Orion and Meade fit into this equation? Do either GSO or Synta make the mirrors for their dobsonians or do they make their own?

Ta

[sopticals]

Meade=GSO
Orion=Synta

[inertia8]

Thank you.

[inertia8]

One more Q.

In previous comparison threads on this forum between GSO vs Skywatcher it was made mention of the GSO having a superior crayford focuser. Is this still the case or has Skywatcher now updated their focuser to be on-par with the GSO?

[Amaranthus]

The Skywatcher now arguably has a (slightly) better focuser. It is a linear power focusser and is lower profile than the GSO one. However, the GSO astrograph includes a mirror fan, and costs less. So it's a toss up.

[knightrider]

I'm looking at a second scope ATM.

I have a 10" Synta which is good, but I am considering a 6" dobsonian as a grab and go.

Are there quality differences between the gso and synta models of this size?

I do believe the synta ones don't put pyrex glass in the 6". And none of the 6" models include a 10:1 focuser...

Anything I should be looking out for?

[Satchmo]

Alex my 2c - surface ripple causes a very near field scatter to a star image so less ripple might give the impression of sharper star image . Whilst it is a highly technical field ,there is no optical physics around that can attribute a darker sky background to a 'smoother' mirror say between an optically rough mirror of 1/20 RMS ripple at the few mm scale and one of 1/100 RMS ripple. That is nonsense peddled by Zambuto et al . Background sky brightness is acutely sensitive to exit pupil also - it needs to be matched perfectly for a good test and of course the same eyepiece used .

I would guess the improvement in sharpness is down to a better smoother figure , and the better sky contrast is down to better quality coatings that are packed down a lot tighter for less scatter . If you don't believe that al coatings scatter light and lower sky contrast try this test . Grab a large diagonal and compare the sky contrast between looking through a binocular, then get the same view but putting a diagonal at 45 degree in the path in front of the objective. The difference will be tangible.

[mental4astro]

When building a scope, mass production or custom, there comes a point where producing a scope costs exactly the same, be it a 4" or 10". In the end, to cut costs it becomes a function of components & care in assembly. At f/8, primary mirror is likely to be spherical as these are cheaper to fabricate. As you've noticed, the 6" has a simple single speed focuser. It also may only have rubber I-rings instead of springs in the primary mirror cell - you'll never be able to properly collimate the scope if this is the case. You NEED to check this out before you make a purchase. At this year's IIS Astro Camp one participant's brand new 6" dob had O-rings, not springs. We also couldn't get the secondary mirror 100% collimated as the spider was placed too high above the focuser. We fixed up their scope as best we could, and the image quality improved markedly - but not to what it should be.

You get what you pay for.

Mark, I didn't think of coating quality also being a factor. Thanks for that :)

[knightrider]

Thanks for your input Alex, it was very informative as I wasn't aware of the lack of springs. How though would I go about checking for springs? Is it just a case of looking at the back of the mirror cell? I can check them that way on my current dob.

Other things I've noted by looking at the information on the sales sites is that the Skywatcher/Saxon/Synta models offer 2"/1.25" focuser and tension control handles for the Alt....whereas the GSO model doesn't seem to offer any of this.

[inertia8]

Correct, it would appear that Synta has upgraded their 6" to include the improvements made to 8" and above models, whereas GSO is still showing the spring tension and 1.25" crayford focuser

[Steffen]

GSO Dobs haven't had spring Alt tensioners for many (5+) years. They have the best and smoothest Alt tension adjustment mechanism of all current mass-produced Dobs. They also allow for rebalancing of the tube, in case you use heavy accessories at either end.

Cheers
Steffen.

[glend]

Just to add further to Steffen's remarks, the GSO Alt bearng are real steel roller bearing assemblies and very smooth and the resistance is easily controlled by the large knurlled nobs. I have disassembed them in he past to add encoders, which is not hard to do, and can vouche for the quality. The tube balance slider is graduated to insure bilateral accuracy and is easy to adjust but the tube has to be out of the base to do so. Some people like to bag GSO scopes, (but never their owners) as but they are the best value performers in the market and mirror qualiity is outstandng - for their price.

[knightrider]

Lots of good points here. From what I can see (not what I've experienced, because I haven't seen one of this size in person) the 6" GSO retains the alt tension spring and doesn't have the balance slider...? Please correct me if I'm wrong.

The synta's focuser although 2"/1.25" is rack and pinion, not crayford....EDIT: I'm not sure if this is true now, I've read from another site it is a crayford...?
I'm certain that the quality of the mirrors of both of these in 6" would be more than adequate for visual use.

[Steffen]

Good point. TBH, I didn't think the 6" GSO Dob was still made. I thought Lee Andrews hasn't had them on his website for a while, but it seems he does. Also, I see that Bintel have them on their site, and the picture shows the old Alt bearing. Maybe it's old stock?

Cheers
Steffen.

[knightrider]

Perhaps. I noticed they're no longer listed on the GS site also. Bintel & Andrews still have them, although the image on Andrews looks more like an 8" used to depict the 6".

I've made a correction on my other post. I've seen on Astro Pete's the Synta 6" does use a Crayford focuser, whereas I've read on another it's a rack & pinion. I'm not sure what to believe.

I have access to inspect a Synta at an Aus Geo store, but unable to inspect a GSO model personally. I suppose an email to the supplier would go a long way to answer some questions.

[jak001]

First post here

I’m looking into getting an 8” dob as a starting point. I’ve been reading over the past few days about which brand to get, but I’m still confused.

What I understand so far;
Synta (Skywatcher + Saxon) have better OTA construction but a worse focuser and base

GSO has worse OTA construction but better focuser, base and collimation knobs.

Points of confusion;
Is the differences in OTA construction between the two brands just splitting hairs, or is it something that a beginner would realistically notice?

Are the flaws in GSO’s OTA fixable by tinkering like outlined in this article http://www.iceinspace.com.au/63-206-0-0-1-0.html (from 2005) or are they more fundamental flaws in resent years?

[barx1963]

Hi Jak
Both brands are generally OK. GSO have really improved their product in recent years with an excellent focuser and the collimation system is much better with knobs which don't need tools and I believe heavier duty springs.
From what I have seen the Skywatcher focusers can be a little confusing as they have separate adaptors for 2" and 1.25" which often causes confusion.
Most people find that the differences are minimal, either brand will serve as an excellent introduction to visual astronomy.

Cheers

Malcolm

[glend]

There is nothing wrong with GSO OTA construction. Keep in mind that everything is built to a price point and in general you get what you pay for, until you get to the point where your just spending money on a brand name or exclusivity. GSO scopes are excellent value for money but do not have the Televue mystic.

[jak001]

cool, thanks for help guys :)