First Scope choice. 10 or 12 inc Dobsonian.

[astrobayan (Bayan)]

Hi all, I will be purchasing my first scope in a few days and I have narrowed my choice down to 2 scopes;

Skywatcher Black Diamond FLEX-DOB 10" for $749 from andrewscom
and
Guan Sheng GS-980 12" ASDX for $849 from andrewscom


Primary use will be observing stars/nebula and might have a look at some planets every now and then. It doesn't really matter if it is collapsible or not.

I do like the extra 2" on Guan Sheng but I am not familiar with telescope makers and their reputation for making quality scopes, which of the two should I choose?

Thanks in advance

[loki78 (Jon)]

Quality wise GSO will be fine for what you want, when compared to skywatcher at any rate.

Keep in mind though being your first scopes, that they are both *big* scopes, the 12" solid tube especially so consider how much you will need to be moving it around as well as a factor in your decision as well as storage.

If possible I'd suggest going to a shop and seeing in person the size and getting an idea of their weight and space they will take up. And if possible for you go to an amateur club or star party and try to get a look through a 10" and 12" and see the difference for yourself.

[Allan_L (Allan)]

Hi Bayan,
Welcome to IIS

I agree exactly with Jon.
Skywatcher is slightly better reputation.
The primary may be pyrex (instead of glass) which may be better quality.
But the GSO (Guan Sheng Optics) is gaining a reputation for quality and is where a lot of other scopres are being made (and re-badged) anyway.

The golden rules:
1. Size does matter. Generally go for the biggest aperture you can afford. The increase in light gathering will mean fainter objects appear easier to see with better contrast.
2. Get the scope you will use most. A 12inch solid tube scope is going to be heavy and awkward to move around. Depending on your size and strength, it may be too big for some people to move easily. Whereas the collapsible dob is much easier to lug around. So how far will you need to move it from storage to observing locations? Are there steps in that path?

Finally, what accessories are presented with each, and/or what additional expenditure will you need to buy for each. Most people with a collapsible eventually want a shroud. Do either have a cooling fan built in? Does either have micro-focuser included? What eyepieces are included (is a barlow)?

Both will probably need a collimating tool to get the best from. But do either have easier to use collimation screws (you don't want to be pointing a screw driver at your mirrors in the dark).

I also agree with Jon that the best advice is to get to an observing session to see both scopes (possibly) or talk to owners.

I agree its a tough decision. I think I would go for the 12" if all other considerations were equal.
But either way, the two scopes you have targeted should both provide excellent viewing.

(I actually do own a SW 10" collapsible DOB and I really do like it.
But I am still considering to go 12" or 14" if price is right) and collapsible is my preferred style. And pyrex would be preferred mirror type. (IMHO)

[brian nordstrom (As avatar)]

Hmm , Bayan , as said here on your thread , the 12 inch is a big scope , so are you a big strong person ? hope so because the views the 12 inch you are thinking will blow you away on all objects .
.
Big scope ..Heavy scope .. but awsome .

The 10 inch is a lot smaller and lighter , but as I am lead to bieleve the collumation issues with a tube design can be a hassle ? for some , . And will give great views also , some say the jump from 10 to 12 inches aint that big in brightness of the views , but each to his or her own
2 great scope's mate , .
I am a 6 ft tall 115kg male with a 4x4 ute and if it was my descision , I would go for the 12 inch , thats getting into deep sky material , and a lifetimes observing , one out lay $$ wise . ( except the accesories , that will follow .. )
Brian.

[Shark Bait (Stu)]

I ended up buying a 12" SW flex tube dob. It was the biggest size scope that I could manage as far as weight and portability issues were taken into account. It was not long until it grew some castors. The views are very good, even through average quality eyepieces.

If you can deal with the size and weight go for the 12".

[dannat (Daniel)]

If it were e I'd get the 10", I know the 12 gathers more light but I reckon the 10" hits a sweet spot for size, you'll fit it in most cars,the 12" prob not.
I had a 12", got rid of it cod it was just slightly too big

[astrobayan (Bayan)]

Thanks for all your replies.

I am a 178CM tall male and I wont have any issues carrying the 12" scope around with me. I can store it in my garage and take it for viewing (about 20mins drive) out in the country.

GSO seems to have a cooling fan and seems to be made from glass. I have asked the shop about the lens material on skywatcher and if it has cooling fan on it. Also if it has knurled collimation knob.

If Skywatcher has cooling fan and knurled collimation knob and uses pyrex mirror should I go with skywatcher?

[loki78 (Jon)]

If you're confident that the size and weight of either scope won't factor in your decision, then I agree with what was said earlier. Aperture wins and go the 12".

Just be really really sure of the bulk first. It will be fine at the beginning. But you don't want the size of it to become a chore at 2am in winter when that perfect seeing opportunity arises to go out and take a peak at things only to then thing of the scope and realise it's just too big to be bothered making the effort.

As the saying goes, the best scope is the one you will use the most.

[wavelandscott (Scott)]

If you have not bought one yet I would encourage you to stop by a retail shop and "see" the size and shape of the 12 inch scope.

Either the 10 or 12 will give you great views but get the one you will use the most.

Cheers,

[naskies (Dave)]

I have a 10" flex tube Skywatcher dob for observing with family, and something to do while imaging.

I had also agonized over the 10 vs 12 decision, but as soon as I saw the size of then in person, my mind was made up. It's not the weight per se tht's problematic - the sheer size is hard to manoeuvre, and the centre of mass is very awkward being so far in front of your body.

Don't forget to get a decent observing chair. You may also want to think about a dew solution (primary doesn't dew up for me, secondary only under really nasty conditions, eyepieces + finder every time).

[Allan_L (Allan)]

Originally Posted by astrobayan

Thanks for all your replies.

I am a 178CM tall male and I wont have any issues carrying the 12" scope around with me. I can store it in my garage and take it for viewing (about 20mins drive) out in the country.

GSO seems to have a cooling fan and seems to be made from glass. I have asked the shop about the lens material on skywatcher and if it has cooling fan on it. Also if it has knurled collimation knob.

If Skywatcher has cooling fan and knurled collimation knob and uses pyrex mirror should I go with skywatcher?

Some people say:
The main advantage of the (Skywatchers') Pyrex mirror is that besides cooling down quicker it tracks temperature changes during the night better than a plate glass mirror. No need for a fan.
Others have thought a SW mirror coating is better quality and lasts longer.
Others say that the GSO has so many other better options that it is better quality (eg dual speed crayford focuser, included cooling fan.)

Another thing, if you can get one with a right angle finder, thats a big difference too.

As you can see, its a tough decision.
One you have to make yourself.
Because people value different features differently.

[Irish stargazer (John)]

I went for a 12" when I bought my Dob late last Year. The full tube GSO would not it in our Camry so I got a lightbridge. I often lug the assembled optical tube outside in one piece if it is clear out but it breaks down quickly into small manageable pieces for loading into the car and can be reassembled and colimated in minutes . Fits nicely in the back of our new Forester so no bending my back to lift it out of the car.

[cjamo9 (Clinton)]

i have a 12 inch bintel solid tube dob. it lives in the carport with one of the silver covers from ebay on it when not in use. its the older style with the teflon sliders. ive fitted a lazy susan bearing to the base and it spins easily now. i see they have the adjustible tension nobs on the tube now( got to better than taking one of the springs off) i have made a trolly to move it around cause set up it is nasty to drag. at high mag its a bugger to keep say planets in sight and once you lose it it takes an eyepiece change(or zoom) to line it up for another 5 seconds veiwing. wide field views are fantastic, so much stuff up there. for high mag id look for some tracking dob with a goto mount. the goto mount from andrews is the next purchase id like to make, have to save up for it though$$.

[EricB (Eric)]

I too hesitated beween a 10" and a 12" dobsonian. I ended up getting the 10" SW flex GOTO. i am very happy with it. It's relatively easy to move around and offers great views. A two speed focusser and a right-angle viewfinder would have been a bonus. Although I am very happy with my choice, I wonder what it would have been like if I had bought the 12"...