8" or 10" Dob

cookiemonster (Anna) · #1 16-02-2011, 01:40 PM

Hi everyone.
I've been reading the forums for a while looking for advice on first scopes. I am planning on joining my local club and going to meetings etc, and doing all the things that have been recommended for beginners. It's all fantastic advice!

What I want is some advice regarding differences in portability (and therefore utility) between the 8" and 10" scopes. Is there a real difference between carrying them outside and setting up?

Thanks

Waxing_Gibbous (Peter) · #2 16-02-2011, 03:04 PM

Hi and welcome to IIS.
Yes. There is a difference.
While a 10" is by no means unmanageable, it is still a good way less manageable than an 8".
I started out with a 12", went to a 10" and wound up with an 8"!!
The beauty of an 8" Newt is (providing its not a collapsible design), you can also mount it fairly easily on a decent Alt/Az mount, making it even easier to use.
If you do decide to opt for the extra 'grunt' of a 10", my advice FWIW, would be to, if possible, find a permenant spot for it to live outside and use a good quality 'scope cover to keep the elements away.
You'll see far more use from it than if you have to drag it out every session.
Good luck and Clear Skies.
Peter

dannat (Daniel) · #3 16-02-2011, 03:05 PM

I think they are pretty similar length wise 10" bit heftier, usually the 8" has longer focal length so is kinder to cheap ep,s

barx1963 (Malcolm) · #4 16-02-2011, 08:50 PM

I think the big difference with an 8" and a 12" is the level of commitment. Quite frankly you have to be a committed observer to bother carrying a 12" scope outside. That is why I usually recommend an 8". Having used both I know you can do a lot of observing even with some light pollution with an 8" and it is almost a grab and go unit. The 10" dobs obviously fall between. If you are a fit person used to handling bulky objects (and you are comfortable with the extra $$$) go for the 10", if any doubt, get the 8" and see how much you enjoy using it. If after 3 months you find yourself anxiously waiting for the next clear night, it's time to upgrade!

ZeroID (Brent) · #5 17-02-2011, 08:50 AM

Aperture rules. Go the 10" for the extra light gathering power, 1317 vs 840, a significant gain. An 8" is normally f6 and a 10" f5 so they are the same length more or less physically for only an extra 2" of girth. Ok, a little bit heavier and bulkier but if you're reasonably fit the extra aperture is worth it for visual neb views.

cookiemonster (Anna) · #6 17-02-2011, 09:11 AM

Thanks everyone. I think I will go with the 10".

Another question: I was looking at collimation; and it looks as though you need a laser collimator for it to be a one man job with a 10". Is this correct? If so, I will get one of those too.

AG Hybrid (Adrian) · #7 17-02-2011, 11:15 AM

Quote:

Originally Posted by cookiemonster

Thanks everyone. I think I will go with the 10".

Another question: I was looking at collimation; and it looks as though you need a laser collimator for it to be a one man job with a 10". Is this correct? If so, I will get one of those too.

You don't strictly need a laser collimator. But it certainly makes life easier. Collimation becomes an easy one man job, and a 2-3 min job. It will also give good-enough collimation for visual use assuming your secondary mirror is correctly aligned to the focuser already.

StarTrucker (Ian) · #8 18-02-2011, 04:20 PM

Hi, Im going to buy a 10' Dob in the next few weeks. Just how heavy are these things ?? I dont wanna best a gut everytime I want to have a perv !

Ian.

BrisGreg (Greg) · #9 19-02-2011, 12:03 AM

If you buy a 10", I don't think you will be wondering evertime you use the scope if the 8" would have been that much lighter (they are both big scopes) BUT I'm sure everytime you're looking at a faint fuzzie, you'll be wondering how it would look thru a 10"

Incidentally, Bunnings have a great flatbed hand trolley for $40 which works a treat for my 10" collapsible

keni (Ken) · #10 19-02-2011, 12:16 AM

Hi Ian,
I can vouch for what BrisGreg said about the flat trolley.
My mate and I use one to move our 10" Dob around and it's great.
It's stable enough to leave the scope on it while we use it.

There's also an excellent article here for moving your Dob. around safely.
http://www.iceinspace.com.au/63-12-0-0-1-0.html

Ken.

AG Hybrid (Adrian) · #11 19-02-2011, 11:38 PM

Quote:

Originally Posted by BrisGreg

Incidentally, Bunnings have a great flatbed hand trolley for $40 which works a treat for my 10" collapsible

AWWW why didnt i think of that?? That would be perfect for shuffling around my 12".

Liz · #12 20-02-2011, 09:23 AM

Quote:

Originally Posted by cookiemonster

Thanks everyone. I think I will go with the 10".

Another question: I was looking at collimation; and it looks as though you need a laser collimator for it to be a one man job with a 10". Is this correct? If so, I will get one of those too.

Yes CM, a 10" Dob is the way.

It can be a bit heavy and bulky, but views are better than the 8", so worth the extra trouble.

The laser collimater is good also - I am a bad collimater, but aim to perfect that this year, and collimate each session instead of once a year.

mr bruess · #13 21-02-2011, 06:05 AM

The bigger the aperture the better.
I'd go for the 10 inch.
Extra light gathering power

cookiemonster (Anna) · #14 22-02-2011, 03:24 PM

Quote:

Originally Posted by keni

Hi Ian,
I can vouch for what BrisGreg said about the flat trolley.
My mate and I use one to move our 10" Dob around and it's great.
It's stable enough to leave the scope on it while we use it.

There's also an excellent article here for moving your Dob. around safely.
http://www.iceinspace.com.au/63-12-0-0-1-0.html

Ken.

Thanks everyone. Decision made. 10" with a trolley similar to this one. I will let you know how I go! I may well be crashing your meetings some time soon!

ColHut (Colin) · #15 22-02-2011, 11:59 PM

I would recommend that you make sure your trolley has pneumatic tyres. It makes a big difference to the bumps.

regards

stattonb (Statton) · #16 28-02-2011, 04:46 PM

go the 10'' and see if you can get a collapsible so its easier to cart around,but like others suggested get yourself a trolley you will thank yourself for it lol,theres no substitute for aperture 10'' is the way to go.

cookiemonster (Anna) · #17 11-03-2011, 09:26 AM

Thanks everyone for your advice. The scope was for my partner, who is an avid reader of IIS (so i had to be discrete). He loved it! Maybe we will see you at a star party near us soon (Mangrove Mountain)!!

Liz · #18 11-03-2011, 12:11 PM

Glad to hear he liked it Anna.

AstroGuy · #19 11-03-2011, 04:21 PM

Quote:

Originally Posted by cookiemonster

Hi everyone.
I've been reading the forums for a while looking for advice on first scopes. I am planning on joining my local club and going to meetings etc, and doing all the things that have been recommended for beginners. It's all fantastic advice!

What I want is some advice regarding differences in portability (and therefore utility) between the 8" and 10" scopes. Is there a real difference between carrying them outside and setting up?

Thanks

Depends how strong you are!

Of course, truss Dobs are more compact to cart around in the car etc...

Benboy (Ben) · #20 28-03-2011, 07:21 PM

So next question would be is a 12" that much harder to cart around than a 10"? Im looking at upgrading my 6" Dob and I think I might have aperature fever.