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10" or 12" dob for red zone

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#1 john@dps

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Posted 10 February 2013 - 04:14 PM

Hi all, I'm a noob and wanted opinions on getting a 10" or 12" for my back yard red zone in LA. I have a 80mm orion right now that i play with in my backyard, 90% of viewing is done there. Im lazy and like to just pull it out and look. The dob will be stored in my detached garage so cool down will not be a problem however the difference in price between the orion 10g and 12g is 500 clams and i really dont want to waste the money if the red zone is going to keep me from resolving good views. And besides a 10g and a paracorr equal just the 12g by itself. Thanks all in advance. I'm also still young and strapping enough to muscle both so weight isn't an issue.

#2 Raginar

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Posted 10 February 2013 - 04:19 PM

Welcome to CN!!! :)

The difference isn't going to be where you live but really what you want to deal with weight-wise. A 12" dob (solid tube) is listed on Orion's website @ nearly 83#. I'm sure a 10" is a little better than that.

Size matters for resolving detail but if it hinders you dragging it outside.. and I realize you think 80# won't bother you... trust me, it gets old and will detract from you using your scope. I'm military, healthy, and it caused me to build a ROR shed so I didn't have to setup constantly!

#3 john@dps

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Posted 10 February 2013 - 04:23 PM

i'm putting it on wheels so i dont even have to lift it.

#4 john@dps

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Posted 10 February 2013 - 04:26 PM

My real concern is the extra money for the 12 if it is not going to be worth the money in my LA backyard

#5 Madratter

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Posted 10 February 2013 - 04:34 PM

You could be in downtown Chicago and the 12" would show more if you take it out. That last part is the key. The 12" isn't necessarily better if you don't take it out as often as you would the 10".

#6 john@dps

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Posted 10 February 2013 - 04:48 PM

Thats what I'm looking for, just to know that the 12 is really worth the extra money. If my red zone is not going to have much of an effect than I will be getting the 12.

#7 kenrenard

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Posted 10 February 2013 - 05:32 PM

I think if you are putting wheels on it should show more. You can always take it out quickly if its on wheels I have my dob on a hand truck and it makes a quick setup with no effort. If you don't mind the size might as well go for it.

Ken

#8 kenrenard

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Posted 10 February 2013 - 05:35 PM

You also may want to ask around about either buying a per flocked or flocking the tube yourself from what I have read it helps with seeing in the city.

#9 john@dps

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Posted 10 February 2013 - 05:50 PM

I will check into that, I would like to do as much as I can, since I can't turn off LA's lights.

#10 City Kid

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Posted 10 February 2013 - 06:00 PM

As long as size and weight isn't an issue I would go with the 12". The difference in views between a 10" and 12" aren't jaw dropping but the difference is noticeable. Just be sure the difference in size truly doesn't matter. I have an 8", 10", and 12.5" dobs and the difference in size between the 10" and the 12.5" seems huge compared to the difference between the 8" and 10".

#11 Pinbout

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Posted 10 February 2013 - 06:07 PM

Im lazy and like to just pull it out and look.



then I'd get a 8in f6. it will show you a lot with little effort, a nice eyepiece sitting height.

#12 GeneT

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Posted 10 February 2013 - 06:15 PM

Given your circumstances, I would recommend the 12.

#13 john@dps

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Posted 10 February 2013 - 06:17 PM

With my 80mm I get to be lazy and just pick it up. With the dob I will just roll it out :grin:

#14 Jon Isaacs

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Posted 10 February 2013 - 07:16 PM

With my 80mm I get to be lazy and just pick it up. With the dob I will just roll it out :grin:


Sometime in the future you may decide to take your scope, load up your car or truck and head out for some clear, dark skies. This is when the 12 inch longer Tube of the 12 inch can be a problem. A 10 inch F/5 fits across the back seat of most cars, the large, longer tube of the 12 inch F/5 can be a problem.

Jon

#15 TexasRed

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Posted 10 February 2013 - 07:37 PM

I got my XT12g a few months before moving to my current blue zone while I was still living in the heart of Dallas/Ft. Worth area, which is a large white zone. I set it up there in my front yard across the street from a street light just to test it out and expected to be able to see very little. I was amazed at what that scope could find and show me even from such a bad location!

Get the 12". The extra aperture is definitely worth it, if the size and weight is not a problem.

You'll also want Orion's SkyGlow filter (the imaging filter is a little better) and their UltraBlock filter. The UltraBlock filter is especially useful and effective for a wide variety of targets.

Flocking is really only useful for reducing the damage done to your views by stray light entering the tube. A homemade "dew shield" extending the tube by an exta foot or so will be just as helpful. Having a spot to observe where you will be shielded from direct light will be essential. If you don't have one, plan to drape something over your head or wear something with a hood to block light from your eyes.

Aperture rules when it comes to cutting through light pollution for everything except galaxies. No filter but dark skies will help with those. Your 12" will definitely not be wasted, though.

#16 Mike4242

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Posted 10 February 2013 - 07:45 PM

IMO, a 10" F/5 dob is the largest that remains easily portable. My 10" F/4.7 fits across the backseat of my VW Jetta just barely. There's no way I could get a 12" in there for transport to the club's dark site unless I got a truss tube. An observing buddy of mine has the Orion truss tube 12" goto dob and the size difference between mine and his is pretty big. His set up time is considerably longer too since he has to assemble the trusses and collimate. The 12" does show slightly brighter images, but it is by no means a jaw dropping difference.

#17 JohnMurphyRN

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Posted 10 February 2013 - 07:57 PM

I have a solid tube 12.5". Fits in passenger seat of my truck. I use it as much as I would a 10". It fits through my back door and my 17.5" doesn't, so it gets used when the ground is mushy and I don't want to roll the 17.5" around the wet grass.

#18 john@dps

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Posted 10 February 2013 - 08:21 PM

Transporting is not a problem either, I have a ford flex and two crew cab pickup trucks. All the seats fold in the flex and when their down it is over 8' long. Though I don't see myself going anywhere but a few times a year, maybe. I'm glad the opinions are for the 12" because I really wanted the largest I could afford. I'm also lucky in the fact I view from behind my garage which has no stray light sources.

#19 PhaedrusUpshaw

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Posted 10 February 2013 - 11:36 PM

Aperture rules, with all other considerations being equal, aperture rules!
Clear skies,
Bill

#20 newtoskies

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Posted 11 February 2013 - 02:04 AM

Both are good dobs, go with the 12". I missed out on a 12" solid tube on CL. Wish I had grabbed it now.

#21 john@dps

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Posted 11 February 2013 - 03:37 PM

For all of you who have stored your dobs in a detached garage, I assume that cool down time is not an issue or if it is its a small one. Am I right?

#22 Tony Flanders

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Posted 11 February 2013 - 04:14 PM

For all of you who have stored your dobs in a detached garage, I assume that cool down time is not an issue or if it is its a small one. Am I right?


Storing a scope in a detached garage helps, but by no means does it eliminate cool-down time. Even with the doors wide open, structures store a lot of heat.

#23 Achernar

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Posted 11 February 2013 - 04:41 PM

The cool down times will be shorter, but there's no avoiding the need to give the telescope time to cool down to ambient temperature. A 12-volt fan on the mirror cell helps a lot, it need not move a lot of air, but as long as it gets air to circulate around the mirror, you will be ready to go much sooner than not using a fan.

Taras

#24 john@dps

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Posted 11 February 2013 - 05:02 PM

I wont be getting a mounted fan till later, but my plan was since I view at home I was going to use a small house fan at the base to blow air between the mount and tube. I thought that would be enough for now since I have power to plug into at home.

#25 Achernar

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Posted 11 February 2013 - 07:25 PM

That would work too, but it won't speed up the cooling because glass is an extremely good insulator in more ways than one. A telescope is a great doghouse for a slab of material with a lot of thermal inertia, and therefore heat stored in it has to get from the interior to the surface. As for a cooling fan, I made mine from 12-volt fans that normally are found in personal computers. I wired them up with a switch, fuse and a red LED to indicate they are on. On the 15-inch, I use a variable resistor to control the speed, I run it all the time at low speed because a 15-inch mirror that is 1 5/8" thick takes quite a while to cool, even when in a truss-tube with an open steel frame tailgate supporting it.

As for your OP, you will be very happy with a 10-inch, but a 12-inch does more and noticeably so on galaxies and nebulae. Especially at dark sites, and believe me, you'll want to go to dark skies at least a couple times a year. If you can afford it, I would go for the 12-inch. If not, get a 10-inch and you'll still have a good telescope for both Solar System and deep sky objects.

Taras






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