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  #1  
Old 04-09-2008, 03:34 PM
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pmrid (Peter)
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Observatories for big Dobs

I have a large 16" Dob on a mount that is steel and solid - i.e. a pain in the nadir to move anywhere - so I am confronted by the dilemma of ageing - either I give this thing a permanent home or I sell it and make way for something I can manage better than a small centurion tank.

I've been reading the recent threads on cubbyhouse obs and lovely roll-offs but didn't find the answer to the dilemma of the big Dob. By their nature, they tend to be low to the ground. When horizontal or pointing to near-horizon objects, these observatories become unsuitable because of the high walls. In any design I have attempted on my own, this tends to be the coup-de-grace every time. You need decent walls to give yourself and your scope at zenith sufficient headroom in any observatory. And wind buffeting makes the same demands. So what's the solution.

Peter
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  #2  
Old 04-09-2008, 04:27 PM
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bmitchell82 (Brendan)
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.... You summed it all up in one champ. The scope is too big, and you cant mount it on a Peir.... Sell it and get a slightly smaller "mountable" scope, or figure a way to mount it onto a dovetail and then drop either a vid cam or CCD into the ep holder with auto focus so you can sit down comfortably and still do your viewing.... age is a ******* and i know ill get there one day. hopefully ill be deep into astrophotography by then! ehhehe

all i say is no matter which way you go its not a cheap event but worth it because when your to old to move even a modest size scope you will still be able to do the things you love!
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  #3  
Old 04-09-2008, 05:36 PM
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madtuna (Steve)
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Magellan Observatory http://home.goulburn.net.au/~magellan/ has a 24" SDM dob in a 4.5 mtr dome
so it's very do-able
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  #4  
Old 04-09-2008, 06:27 PM
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AlexN
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you could GEM mount the newt up on a pier, but you'd be looking at atleast $20k to do so... probably not feasible...

The domes are the best option for a big dob...
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Old 04-09-2008, 07:18 PM
Rod
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Hi Peter,

Have you thought of having the whole building rotate? I have some pictures of observatories built this way. I could scan a couple for you if that would help.

Rod.
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  #6  
Old 04-09-2008, 07:31 PM
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kinetic (Steve)
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Quote:
Originally Posted by AlexN View Post
you could GEM mount the newt up on a pier, but you'd be looking at atleast $20k to do so... probably not feasible...

The domes are the best option for a big dob...
I agree with Alex and MadTuna Steve,

doable, but maybe less than 20k?

Re the Bartelised option Peter, mine is still a work in progress after
25 odd years, and always to improve my viewing and minimise the
workload as I get older.
When I built my dome I wished I had built it 10 years earlier, it was such
a pleasure to use. My enjoyment of the hobby increased 10fold.
My GEM and dome (as you have seen via the Bartel thread), is a
cheap option.

The Garlitz Fome dome idea can, and has, been scaled up.
Barry( Bloodhound) put his on a high wall, mine's on about a 3ft wall, Joe's
similar to Barry's.

You are obviously practically oriented and half the enjoyment comes
from actually constructing the idea you have in your head.
For me at least.

I say go for it, don't settle for second best.
Someone's signature comes to mind....
Life is too short to look through cheap glass.

regards,
Steve B.
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Old 04-09-2008, 07:35 PM
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Well if you have a permanent setup in an observatory at a dark site then that would be an ideal situation. With a dob you would need a very large (and expensive) dome though, rather than being able to mount a smaller dome on top of an existing structure.

A cheaper option would be a simple roll-off roof shed. Just wouldn't be able view stuff near the horizon.

Another option is to mount the optics in a much lighter structure so it is easier to move and setup. Even the biggest truss dobs can be easily run around using wheel barrow handles and a wagon or covered trailer. Is it a solid tube setup now?

Peter Read at SDM is making Compact versions now and a 16" version with your optics would be very easy to handle. Or build your own. Can also get kits from: http://www.dobstuff.com/

My 16" Tridob is so portable I keep wanting to make a bigger scope!
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  #8  
Old 04-09-2008, 07:48 PM
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pmrid (Peter)
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That would be a start. I'd be glad to see them.
Peter
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  #9  
Old 04-09-2008, 08:37 PM
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Yeah... my prior idea for 20k was probably a bit over-estimated.. It depends on how you do it... If you're able to home build a GEM or get a good one 2nd hand, you'd probably be right....

I was factoring in the price of a Paramount ME.. I suppose a Losmandy Titan would hold the 16" for visual use without issues... and that alone cuts the estimate down to maybe 14k... adding price of good rotatable rings (again if you could build your own, cheaper..)

A home made gem might not cost you too much at all if you have the required tools and access to cheap materials..
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  #10  
Old 04-09-2008, 11:37 PM
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Starkler (Geoff)
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Quote:
Originally Posted by pmrid View Post

By their nature, they tend to be low to the ground. When horizontal or pointing to near-horizon objects, these observatories become unsuitable because of the high walls.
The solution could be as simple as plonking the dob on a paved area and housing it in a cabinet type enclosure with a door and rollers/castors on the bottom, so it can be rolled away from the scope. When in place you could secure it down to eye bolts in concrete.

The nicest dome of all is the night sky
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  #11  
Old 05-09-2008, 12:51 AM
Ian Robinson
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You need a roll off shed - one that is on tracks and can be rolled away from the scope which stays put.

I knew of a fellow who bought a 25" Starsplitter and did just that.
I think he put a toybar hitch on one end and he simply backed up hitched up to his towbar and hey presto , no hard muscle work required . To put the scope away he simply reversed the process.
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  #12  
Old 05-09-2008, 02:54 AM
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Merlin66 (Ken)
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Roll of buildings don't help with the wind etc.
I was targetting a 1.5m wall and a 2.7m roof height observatory for an 18" dobbie. But like you after three back operations I realised I wasn't twenty and Superman any more!! Sold the 18" to Gove, and bought a 12" LX200; the biggest I thought I could handle! I had an 10" LX5 for almost 10 years so thought the 12" would be the same..... wrong!! It's twice the weight and twice as difficult to use on your own!!
Summary:
Either build a low wall observatory or buy a 5" refractor/ 10" SCT.
Remember what they say: the best telescope to have, is the one you will use!!

Last edited by Merlin66; 05-09-2008 at 02:56 AM. Reason: spelling
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