collapsible V Full Tube dobs

[Tejas (Ben)]

Hi Guys
as per my previous thread i have decided on a Dob, now comes a choice.
i can get a 10" collapsible, or a 8" full tube (where i am buying from doesn't have a 10" full tube)

the collapsables need more collimation than solids i believe, so i would purchase a collimator as well.

if i buy the 8" i could afford to buy the Celestron Telescope Eyepiece & Filter Kit (the one in the aluminium case) where as with the 10" i'd need to make do for a while with the included eye pieces.

i'm also wondering about light leakage on the collapsable as well.. does much light get in when being used in a lit area? i would use mine a bit in my front yard and have a street light diagonly opposite my house

[Allan]

Ben, aperture is king. If you can't buy a 10" full tube from your local store, find another store. A truss Dob cannot compete with a tube Dob of the same size for contrast. I almost bought a 12" truss Dob but realised a tube would fit in my car so bought that. The collimation never changes in my tube.

My suggestion is you spend a little more now on your telescope, and patiently buy better eyepieces as you can afford them.

[atman (Mark)]

Hi Ben,

After agonizing for months whether to spend $500 on a telescope, I got an 8" dob.

2 weeks later I went back to the shop for a barlow and stood staring at the 10" model - wishing I had paid $200 more for it.

A month later I realised I should have got a 12" model.

imho hang out and get the big one. You wont regret it.

Mark

[barx1963 (Malcolm)]

No matter what scope you buy, aperture fever always strikes about 2 weeks later.

You should get in the habit of collimating newts each time you use it, whether solid or truss. Remember, with collimation, do not solely rely on a laser collimator, a Cheshire will give best results and you can use the laser to tweak or if setting up after dark.

Light leakage can be an issue but a simple shroud can solve that problem.

I am not a big fan of the eyepiece and filter kits unless your scope comes without any eps. Even then I would recommend a beginner buy a 25mm and 15mm plossl and save their cash for some really good EPs later on when they know what they want.

Malcolm

[rustigsmed (Russell)]

If you can afford and move/lift a 10" (or 12") go for it.
I wouldn't worry about flexitubes flexing etc. i've got a 12" and its fantastic. there are also advantages of flexitubes, less turbulance when getting the scope to temp, easier to move and store. collimation will need to be done regardless of solid tube or truss. infact i find it easier to collimate with flexitube as you can look directly at the secondary mirror whilst adjusting the primary (when using a barlowed laser).

all the best!

[glend (Glen)]

Look there are benefits of both solid and truss dobs, it comes down to the individuals preferences. Go for the biggest you can afford, and will probably be a solid tube because they have a cost advantage. I am retired and have no trouble moving my 12" dob around, there are ways to make it easy.

[StarVoyager]

Check out this thread which has some discussion on the benefits of full tube, versus open tube designs: http://www.iceinspace.com.au/forum/showthread.php?t=104351. See from post 10.

Cheers.

[AG Hybrid (Adrian)]

Originally Posted by Allan

A truss Dob cannot compete with a tube Dob of the same size for contrast. I almost bought a 12" truss Dob but realised a tube would fit in my car so bought that. The collimation never changes in my tube.

If you say so. If you had a problem with a big tube and bought the truss/collapsible instead, it would have fit in your car...

[Tejas (Ben)]

i got a 10" collapsable from astro petes for the same price as a full tube from other prices.
picked it up this morning. bring on nightfall now

[mental4astro (Alexander)]

My 17.5", from this:



To, now you see it:



Now you don't:



What used to occupy the entire length of the passenger side of my Mazda Tribute, from glove box to rear gate, now sits in half the boot space. Contrast drop? Maybe. Would I prefer a tiny increase in contrast to a much more user friendly scope? Not a chance. Collimation more touchy? Nope, no more than any other Newtonian that is regularly transported. Designed properly, a collapsible dob is a very fine instrument.

[shenanigans000 (Greg)]

Originally Posted by Tejas

...and have a street light diagonly opposite my house

The first accessory I would recommend is an air rifle. This will assist in reducing the light pollution caused by that street light.

[CJ (Chris)]

Just a thought from a newbie.
I read somewhere that truss dobs, even with a shroud, are not at all suitable for solar use. Makes sense to me, but the more experienced here may think using a 8/10" dob for solar viewing is a daft idea full stop!