Any reviews on Guan Sheng 10" Dobson from Andrews Communications?

[Draco]

Hi.

Its me again ;) I have ditched my idea of getting a binoculars or Orion Shorttube and am now looking at getting a Guan Shen 10" Dobson (is this GSO?) from Andrews. The reason being that with a tripod, the binoculars/shorttube was not that much cheaper than getting a 10" Dob. I know a binoculars is really good for "grab and go" situations but for now, I would like more resolution :D

The 10" Guan Shen is currently selling for $599 at Andrews Communications. I would have got the 12" however I have a small hatchback and max it can fit on the backseat is 1300mm.

I don't the money at the moment to get a truss/collapsible one unfortunately :(

Anyhow, does anyone currently own a Guan Sheng 10" Dobson from Andrews? How are these? Also, is this the same as the Bintel Dobsons (GSOs rebadged as Bintel) ?

Thank you

[niko]

Draco,

The GSO 10" is a great scope and Andrews are good to deal with. You will enjoy the views from it for a long time to come.

Essentially the GSO and Bintel solid tube dobs are the same beat

good luck

niko

[Draco]

Thanks Nico. That means alot .. just wishing for clear skies once I get my Dobson ;)

Would I need to get a collimator as well? If so, which one will be good? The reason I ask is because I have read a few places that Dobsons lose their collimation quite a bit.

BTW when you say collimating a Dobson, does it mean making sure the finderscope and the dobson are looking at the same place?

[niko]

No Problems....once you make the purchase you will bring on cloudy skies in your city for a week - it's just what happens when you buy new gear!

No, getting the scope and finderscope pointing to the same spot is just the alignment of the 2 - this can be done during the day on any reasonably distant object (be very careful of the sun!)

Collimation is aligning the primary and secondary mirrors to ensure you get the best views at the eyepiece. Solid tube dobs hold their collimation reasonably well so you shouldn't have to do it every time and being a little out of collimation is not the end of the world.

I think many people user a laser collimator and some do a final check with a cheshire one but I'm not an expert.

I think andy's shot glass tutorial might help - http://www.andysshotglass.com/Collimating.html

niko

[raymo]

Hi Draco, You should really try to find an extra $100 and get the Skywatcher 10"collapsible. It is so much easier to move around, and can be secured on the back seat with the seat belts The collimation is not affected by collapsing it. I had mine 3yrs. and tweaked the collimation
twice in that time. You can get laser collimators very cheaply these days,
about$35-40. I paid $110 for mine a while ago.
raymo

[Draco]

Hi Raymo.

How is the quality of Skywatcher compared to GSO? Is it similar or Skywatcher is superior to GSO?

Since both at 10" I am guessing the weight of the tube will be similar. If the only thing separating the two is the length of the tube, then I might still consider GSO since I get a right angle finderscope and 3 plossal eyepieces (9mm,15mm,25mm) from Andrews however for the SkyWatcher, I dont think these are included.

Please let me know

Thank you in advance.

[malclocke]

I've had my GSO 10" dob for about a year now and I love it.

Re portability, it fits across the back seats of my station wagon (just). The base goes in the boot. This is definitely worth checking as you will be wanting to take a scope like this somewhere dark once in a while to get the most out of it.

Collimation is important. The scope is f/4.9, so you have very little margin for error with the alignment. I use a cheshire eyepiece for collimation.

There's a lot of reading about collimation available, read what you can bare to. My favourite links for collimation are:

http://www.skyandtelescope.com/howto/diy/3306876.html
http://www.astro-baby.com/collimation/astro%20babys%20collimation%20guide .htm

If you can get the help of someone experienced to get you started with collimation I'd recommend it. I've had to muddle through on my own for the past year, and have had plenty of wtf moments along the way. It's an essential skill to have though.

I have not owned or used a Skywatcher so can't really make a comparison. Someone at a recent star party who owned a Skywatcher 10" was saying that the base on the GSO is a lot smoother than his Skywatcher, and that the GSO focuser seemed nicer.

It's very hard to get any qualitative comparisons of the optical quality of the 2 brands. Everyone seems to have an opinion on this, I take them all with a pinch of salt.

One decision I had to make was whether to get a red dot finder or a finder scope. I went for a red dot but eventually changed to a GSO right angle finder as the lack of any magnification on the red dot finder just wasn't working for me. Some people swear by their red dot finder though.

Anyway, good luck whatever you decide :)

Malc

[peter_4059]

I've had a 10" GSO dob for about 5 years -now on an EQ mount. Most of my images have been taken through these optics.

[ColHut]

I've had one of these for a few years now. Seems good value for money. I added a Rigel Quick Finder alongside the RACI finderscope. Together its pretty easy to get in line with things. A Telerad would be fine too. It fits in the car but normally I leave it on a $20 moving trolley with pneumatic tyres held on with the packing polystyrene and Ocky straps. Fair compromise between aperture and weight.

regards and welcome :)

[raymo]

Hi again Draco. I have used both GSO and SkyW, and optically there is nothing to choose between them. I suspect the mirrors come from the
same factory. Sky comes with 2 EP's, 10 & 25mm. and straight through
9 x 50 finder. The Sky OTA is approx 14kg, probably slightly heavier
than the GSO, due to the castings and tubes that form the collapsing mechanism. Any difference in swivelling smoothness probably comes
down to individual scopes, being as they are mass produced. I don't
know about the GSO, but you can get the kit to upgrade the Sky to
Go-To.
I personally find R/A finders confusing, owing to the different
optical orientation, and don't like not being able to glance up
along the tube to align with the object I'm looking for. One thing
I really like about the Sky is being able to carry it with one hand by
one of the tubes whilst carrying the base in the other hand, saving
me a trip to and from the car. Anyway, you pays your money and
takes your choice. It's becoming a bit like Holden and Ford.
raymo

[ausastronomer]

Raymo,

You keep offering people advice and it is fairly obvious to me that you are just offering it for the sake of it, without really having much idea of what you are talking about. While you might think you are being helpful, you are not, because you just muddy the waters and the original poster doesn't know who to take notice of.

In regard to your comment which I have requoted above, let me say this:

If you have owned a Newtonian telescope (and it doesn't matter who made it) for 3 years and only tweaked the collimation twice in that time period, one of the following things have happened:-

1) You have only used it twice.

2) You haven't got any idea how to collimate the telescope.

3) You don't care, or take the time to collimate the telescope properly. This is a very common problem with a number of experienced observers and beginners.

4) You have over tightened the primary mirror clips which will prevent the primary mirror from shifting, which may reduce the need to collimate the primary, but will induce astigmatism which will degrade the image quality in any case.

Does anyone else own a collimation free Newtonian like Raymo? I haven't managed to find one in over 40 years of using some of the highest quality newtonians on the planet.

Cheers,
John B

[ausastronomer]

That is also way incorrect. In fact they don't even use the same glass types for the primary mirror substrate. The Skywatcher scopes are made by Synta and use Pyrex glass as the primary mirror substrate and the GSO scopes use BK7 glass as the primary mirror substrate. Synta is in China and GSO is in Taiwan.

Cheers,
John B

[Forgey]

My first scope was the 10"gso dob. Had no problems apart from it being a bit bulky. I now have the 12" skywatcher goto dob and the only reason i upgraded was because i wanted the goto and tracking.
Other than than the 10" gave great views :)

[Cumbrian]

I purchased my 10" dob from Andrews around two months ago. I can have no complaints with either their service or the quality of the product.

I store my scope in my living room (it's a design feature :)). When I move the scope outside I have to do it in two trips, moving the base and the scope separately. If you're planning on taking it to a dark sky site, which I haven't done yet, then you'll want to be parked right next to your set-up place as despite the scope not being two heavy a little walking distance would soon make your arm muscles start to burn!

Admittedley I am a novice and have nothing to compare the scope too but I have certainly enjoyed the last couple of months, when the Brisbane cloud cover has eased.

One problem that I do have, and I suspect looking at your location you will too, is light pollution that is by far the biggest frustration that I face every time I use my scope. Not much that can be done about that though.

I suppose with hindsight maybe a collapsable would have been a little more practical but I'm certainly happy with my purchase.

Enjoy!

[Draco]

Hey Nico

I think the Sky (not Skywatcher ;)) Gods heard that I was talking about getting a Dobson because since late yesterday the skies are pouring .. it has been raining cats and dogs all night and even today :( Sorry in advance to everyone in Sydney for spoiling their clear skies

[Draco]

Thanks Malc.
I checked out those links. They are awesome. I guess once I try them a few times I will appreciate the instructions abit more.. but yay.. greatly appreciated.

[Draco]

Please correct me if I am wrong but I guess the general consensus is that GSO 10" Dobs are great and in par with Skywatcher 10" Collapsible (except for the collapsible feature).

Cumbrian, yes light pollution is a huge problem. I went to Linden last Saturday and you could see the light pollution in Sydney from there .. it was soo bright! Yet in Linden, there was dark skies .. so dark that I could easily see the center of the milky way .. yay! I do plan to take the telescope for night sky viewings and have seen others park close to the viewing area so might do that.

I will go to Andrews and have a feel for the OTA weight and see if it is manageable. It should be ok or I could get a small foldable trolley to cart the OTA

Thank you once again all. For sure, my next telescope will be a 12" Meade Collapsible Dobson.

[Rick Petrie]

John
I didn't think over tightening the primary mirror clips would prevent the primary mirror from "shifting".
It would definitely cause pinched optics and degrade the image quality.
It was my understanding that the primary mirror is mounted with the clips onto the "mirror cell" and it is this cell that is adjusted via the three (3) rear accessed mounting screws and lock screws for collimating purposes, not the primary clips.
Regards Rick:)

[Draco]

I just re-read the specs for the GSO 10" Dobson from Andrews. It says that it comes with a fan for the primary mirror. Does this mean I have to always run the fan to cool the inside of the tube? (which means I have to get a battery pack when I buy the Dob else I wont be able to use it?)

:(

[martyn01]

DOnt get it he tried to sell me an old model after putting up the price $100, he said it was the newest one on his web site and now when you look at the pic on there the knobs are blacked out and changed watch out from them

[Draco]

Hi Martyn01

Are you referring to Andrews .. that I should watch out for Andrews?

[Rick Petrie]

Hi Niv
The purpose of having a fan on a Newtonian/Dobsonian telescope is to cool or bring the mirror to ambient temperature and this will much improve the viewing through the scope. It helps to eliminate the disturbed air caused by the mirror temperature not matching the air around it. (like heat shimmer coming off a road on a hot day)
You can view with no fan attached, but much better views will be obtained with the fan on all the time while viewing as the temperature of the mirror will adjust to closely match the outside air temperature.
Well worth spending a little for batteries to power the fan.
Cheers Rick :)

[Draco]

ah ok. Thanks Rick

[barx1963]

Niv
Just to clarify what Martyn is talking about. The GSO scopes used to have metal knobs on their alt axis. These are now in black plastic. If you look at the Andrews website it shows the knobs blacked out, prseumably to represent the black platic knobs.
Andrews don't spend a lot of money on their website, one of the reasons their prices are good IMHO!
I have dealt with Andrews and bought my 12" GSO dob there and have had no issues.

Malcolm

[barx1963]

Actually, I disagree with Rick. I ran my fan on the 12" for 30 mins to an hour before observing then turned it off. Once the mirrors is cooled to ambient it should be OK unless there is a significant temp change inside a short period.
My reasoning was 2 part. A) batteries are not cheap and didn't want to run them down over a 5/6 hour session B) there is bound to some minute vibration, after all these are only normal computer fans, so turning off makes sense.
In fact my fan stopped working after a while and I found just putting out the scope for an hour elliminated tube currents.
It is easy to see if you have a warm mirror, a defocused star will show clear ripples.

Malcolm

[noeyedeer]

there's a fair few reviews of the GSO 10 incher. you can search Google for the bintel (aus) or zhumel(?) (us version). they're basically rebadged GSO's

I'm saving up for a GSO dob from Andrews ... worth the money from what I've seen and read. and the money saved can be spent on upgrades.

Matt

[Draco]

thanks Malcolm.

I looked at the Andrews website again and did notice the black paintbrush blob ;)

noeyedeer .. yup me too. GSO 10" for me ;)

[Allan_L]

I think the cooling fan comes with a small battery pack that may take a few AA batteries (or the like).

And i agree that viewing with fan off (in most cases) will produce a better (steadier) image.

Rick has a great setup with a vibration free assembly, so he runs his fan continually as an aid to dew deterrent I believe, as well as mirror cooling.

I too have had several dealings with Andrews Communications and found them to be reasonable and honest with me. Luke can be quite helpful. But telescopes is not their core business.
So just don't expect too many frills or whistles. They work to a good price, and not far beyond. Whereas, Bintel may sometimes be a little more expensive, but they have a showroom, and technical staff to provide good customer support, if you need it. Horses for courses.