View Full Version here: : 10" vs 12" Dobsonian?

07-10-2017, 07:46 PM
Hi all, :hi:
I'm looking for a dob to use while my main setup is imaging. I have decided on either a 10-12" scope, as they are both pretty cheap.
Is the light gathering power of a 12" worth it over a lighter/more portable 10" scope?
:question: :thanx:

07-10-2017, 07:51 PM
I found the 10” Dobbie was close to the visual “sweet spot”.
Easy to setup easy to use - I was very happy with mine.

07-10-2017, 07:57 PM
Hi Ken,
Is that just because of the weight of the scope?

07-10-2017, 08:17 PM
Yeah, partly, but the performance was very satisfying.

07-10-2017, 08:37 PM
Hi Logan,

Are these the Dobsonians you are looking at?


Both are quality models, for the extra $270 I personally would go for the 12 inch version (both are F/5). I built a dob myself years ago and used it with a lumicon deep sky filter from suburbia and got fantastic deep space views. The links include the specs listing the relative weight of both OTA's and dobsonian mounts. The best telescope is the one you feel comfortable carrying outside to use. The one which you think you would be motivated to carry out regularly would be the best one for you.

Good luck :thumbsup:


07-10-2017, 08:59 PM
Just a word of warning. In case you should want to take a few snaps
whilst your other rig is doing "serious imaging", many Dobs do not have
enough back focus to allow the attachment of a DSLR. All Skywatcher
ones do, but many others don't, so if it matters to you, I suggest you
speak to Bintel about the matter.

07-10-2017, 09:48 PM
The bigger scope is worthwhile if U are young enough to handle it. The 10 inch may be the wiser buy for the long term if U are over 55.

However, if U are younger, use the bigger scope whilst U can!

07-10-2017, 10:00 PM
Hi Logan,

I wanted exactly the same as you and got a 12". The eyepiece height when looking at zenith is more comfortable as it stands taller and the views are awesome, even from suburban lp. I use a UHC filter on nebulae and a wide field EP. Aperture rules!
It is a bit awkward to handle once you're tired and the tube is covered in dew. Putting it in the car is best done with 2 people and you need station wagon or similar as it doesn't fit on the backseat- a 10" might fit.
I have to find an observing chair at some stage as it gets tiring bending over the eyepiece.

Clear skies!

12-10-2017, 10:40 AM
Having looked through 10"ers and 12"ers many times, I'd say the difference is not worth the extra money and bulk (you do mention portability) based on the visual improvement. I've owned the 10" and 8" versions of these GSO dobs (still have the 8") and noted that the 10", while an excellent general purpose visual instrument, was quite a bit bulkier than it needed to be. Granted, it wasn't much of a problem at the time because I didn't have to travel with it. Also, I was still able to lift and carry the whole thing by myself (just). For some reason the gap between the mirror edge and the inside of the OTA was much wider than in the 8". The OTA was almost 12" outer diameter if I remember correctly. Mount sized accordingly. The 8" is much more portable than the 2" difference would suggest. And these were two scopes of similar focal length. Now, with the 12" vs. 10", you are adding 250mm of focal length on top of the extra diameter and 10kg of weight (30kg vs 40kg total weight). This is a considerable step towards a sore back and away from frequent happy use if you need to take it anywhere but your own backyard. YMMV of course, but will be less with the 12" if you count actual scope carried miles :P

12-10-2017, 12:33 PM
Be aware that Andrews is presently running their 10% off sale (until the 20th), so all GSO and Skywatcher dobs in stock are marked down. Andrews is usually lower cost than Bintel in normal pricing as well.
Now i have owned both a 10" and 12" GSO dobs, and they are good value, with excellent mirrors for the cost. I used a hand truck to move them around at home, so weight wise that was not a factor. If your going to a dark site, the 10" is easier to transport in a vehicle and to load and unload. A Skywatcher collapsible model offers some advantage in handling during transport. Just remember that Seeing conditions determine how often the 12" will give you better views.

12-10-2017, 05:18 PM
The 12" Dob is a big scope! I find my 10" Dob does a perfectly respectable job as a light bucket, AND I can carry it myself. You will probably use it more because of its better portability.

12-10-2017, 05:57 PM
I've had both and currently use the 10".
The 12 makes transporting more difficult. It uses the entire back of the Pajero. !2 gives slightly better views, but I used it less often until it was mounted on a trolley, then I needed a 2 step ladder at the zenith.

12-10-2017, 06:24 PM
+1 from me, 10” is the way to go.

12-10-2017, 08:56 PM
My vote goes to the 10" collapsible, holds collimation amazingly well,
and easily fits seat belted across the back seat of my Corolla,
with the base in the boot.
As the old saying goes, "the best scope is the one that gets used".

12-10-2017, 09:16 PM
Maybe go for a 10" and invest the difference to a 12" into a premium widefiled EP. I used mine with Ploessls for quite some time and the 30mm 2" EP (62deg I think) GSO puts in the box. But adding a 16mm Nagler Type 5 really added Warpdrive to the scope !!!
Xmas is coming and Bintel might have another TV sale on.... just saying :P

12-10-2017, 09:35 PM
If you are young and fit enough go the 12", every inch adds a bit to the experience.

Peter Ward
12-10-2017, 11:05 PM
So...you want to look through it...... or carry it? :)

A no brainer I would have thought... ;)