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jason.p

Why Dob?

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I know this has been discussed at length before, but I really don't understand why the Dobsonian appears to be the scope of choice for so many. Assuming the optics are the same, is it a question of price or ease of set up?

So once the scope is paid for and set up, is it still preferable to a mount? If so, why?

I've got a 200p on an Eq5, and on a Dob Base (albeit homemade ) and much prefer the Eq5.

I know the "Dob brigade" have an enormous following and I certainly don't want to start a war, but i really don't get it.

(Should i get my coat and call a taxi!!)

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Well I think you are off the Christmas card list.

I think it is apperture for cost and you can also get extremely high quality mirrors at a fairly small additional cost.

Now I have  6 scopes a 115mm APO, a 180mm Mak, 190mm Mak/Newt a 30cm SC and a 70mm APO.

When I bought the 18 inch Dob I thought I would use all of the the scopes but 50% of them never see light now, I was told this would happen.

For me it is just the simplicity of it all and the fact that there is not much that can't be seen at all with a big Dob.

An after though, you should get protection :evil: .

Alan

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I suppose that the choice is somewhat between a goto and a dobsonian. I will therefore ignore the other manual options and the driven but non-goto mounts.

A goto is as expected a mount with a computer and some maniacs software that will after being supplied with data and being aligned goto  a selected object. The "idea" is that the scope does the work of finding thing and you need to "know" less. Not in reality I find true as you still need to know what to look for and you must have an idea of where it is, usually exactly where and exactly what. You are paying for the motors and the software, but what do you expect, you buy a car with a motor.

The dobsonian is (was) a simple mount, devised to be such. When you use one you are literally "hugging" the scope, and you gently (hopefully) move the scope to maintain the object in view. The whole idea was that you could either afford a scope on a dobsonian mount or you could afford a bigger scope on a dobsonian mount. If you are any good at DIY then you can run off to B&Q get some 12mm ply and off you go with a jig saw and a file.

I suspect one much liked aspect is the "contact" that you have. No-one is going to hug an EQ5, especially when it is going to the next object.

There are more goto dobsonians around these days but these although a dobsonian start getting into the expensive region again, Synta, Meade, ES etc do not seem to have embraced the idea of just handing out motors and software free yet.

The old saying is "horses for courses".

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For me, ease of use.

If my Skyliner needed the same ammount of setting up with the constant resetting of controls and scope rotation that my Celestron 127 endured, I would have given up by now, especially for visual observations.

That said I would need a tracking EQ mount to photograph Jupiter for an hour, and would not complain about the system, as this is a neccessary requirement.

The late Dobson built and designed the Dobsonian for one simpe reason, to keep it simple and easy to use.

Edited by Charic
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So that an economically poor pleb like me can study the night sky with a reasonable aperture sized mirror...:D

What was it I heard from my late father earlier on this year? Back in the 1960s, a guy in the same town as his bought a 6 inch telescope which cost the earth. The chap who owned it worked hard and saved his pennies to acquire such a 'large' aperture for the time. Probably would have cost the equivalent of a 16 incher today...

Thanks to the Chinese, most people in the UK can own apertures larger than that if they put the money otherwise spent on a basic Sky subscription for a year...

Hang on, look what came up with a Google search to prove my point...

Worth a read: http://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=2773&context=etd

post-3767-0-69321200-1450002456_thumb.jp

post-3767-0-61827500-1450002475_thumb.jp

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That's about the sum of it. Dobs have their draw backs, but overall they are probably the best value for your money.

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It's all about the money and what you want from it.

Everyone has a budget. If you need goto and photography then much of that budget will be in the mechanical aspects and little will be on the, inevitably smaller, telescope. If you are visual and want to see as much as you can then most of your budget will go on the optical tube itself and the mount has to be simple and low cost.

It is also easier for the average person to make a Dobsonian using basic tools. It requires more than basic tools to make a GEM.

Your choice.

Nigel

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I am another that find the dob design odd the eyepiece is allways in the most backbreaking positions and the constant nudging annoying give me an EQ mounted newt anytime.

Alan

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I know this has been discussed at length before, but I really don't understand why the Dobsonian appears to be the scope of choice for so many. Assuming the optics are the same, is it a question of price or ease of set up?

So once the scope is paid for and set up, is it still preferable to a mount? If so, why?

I've got a 200p on an Eq5, and on a Dob Base (albeit homemade ) and much prefer the Eq5.

I know the "Dob brigade" have an enormous following and I certainly don't want to start a war, but i really don't get it.

(Should i get my coat and call a taxi!!)

i wouldnt bother with a taxi, best getting on a plane :grin:

I am another that find the dob design odd the eyepiece is allways in the most backbreaking positions and the constant nudging annoying give me an EQ mounted newt anytime.

Alan

each to there own and all that, but i find if your mount is set right and the preload is set good on all the friction pads it glides lovely , and the ep is always in a comfortable position. when you use a eq mount you have to rotate it in the rings to put the ep were you want it how is that a good design for visual. :smiley:

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As I'm almost 100% imaging I would have no use for a dob, and even when I was visual I found a driven eq mount much more conducive to observing. Even an undriven mount as my old 8"newt was on was better as I only had to nudge one axis. If I left the scope for any reason even the un driven mount was easy to just push round and the object was in the field. For the driven mount it was there anyway.

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My problem is that I have to stand when observing and cant bend without great pain so unless I was four foot tall a Dob is to painful to use, with an eq you can allways get the eyepiece into a comfortable position.

Alan

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As in all matters of taste, belief, preference, etc, etc, it is pointless discussing it.

There is no right or wrong - it's just what you prefer for your own private reasons,

and... you don't have to justify your choices. 

I don't care what your preference is, I will not try to change it, or try to convince you that you are somewhat wrong :grin:

I don't understand this business of treating this as a matter of for or against :confused:

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I tell my friends who are looking at buying a scope to set a budget , then decide if they want to find things manually and be able to see them or find things automatically but barely make out what it is they're seeing

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My problem is that I have to stand when observing and cant bend without great pain so unless I was four foot tall a Dob is to painful to use, with an eq you can allways get the eyepiece into a comfortable position.

Alan

easy answer to that, get a bigger dob :grin:

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For me its simplicity.

When observing something like a faint galaxy cluster I love a dob's ability to just move wherever you want it to go immediately. No fussing about trying to locate a control knob, a handset. or loosening clutches. Simply grab the scope and you're off. it moves at any speed and in any direction I want. I love this ability.

I can also move from one area of the sky to another without the need to twist the scope around in its tube rings so as to try and reach the eyepiece. 

Simples :)

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When using a dob, I feel "bonded" to the scope or part of it somehow, these things seem to be a natural extension of our body and are instinctive to use.

In contrast I find refractors put me through a yoga/gymnastics lesson when viewing near the zenith, as I try to do. I do like refractors btw...

Even if the price per inch of aperture was the same I would still buy the dob :smiley:

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How much did the EQ5 cost you?

I paid £200 for the OTA, EQ5 and tripod.

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Well I think you are off the Christmas card list.

I think it is apperture for cost and you can also get extremely high quality mirrors at a fairly small additional cost.

Now I have  6 scopes a 115mm APO, a 180mm Mak, 190mm Mak/Newt a 30cm SC and a 70mm APO.

When I bought the 18 inch Dob I thought I would use all of the the scopes but 50% of them never see light now, I was told this would happen.

For me it is just the simplicity of it all and the fact that there is not much that can't be seen at all with a big Dob.

An after though, you should get protection :evil: .

Alan

Sorry to hear you feel like this.

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I paid well under £500 for my 12" F/5.3 dob. If it was mounted in any other way it would not be portable or affordable so I'd have to have a smaller aperture scope. The 12" has shown me the best views of the skies I've had in my 30+ years in the hobby. As has been said, we have lots of options to select from and each of us will have different priorities and make different choices. We are all in the same hobby though :smiley:

Sorry to hear you feel like this.

Alan was joking I'm sure.

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I have just found another great advantage of a Dob by chance.

I was going to use the Mak/Newt tonight as it is a nice scope and has not seen action for a long time, I placed it on the AZ EQ 6 and the sky decided to become patchy. This being the case I cannot polar align and even if I could some stars are behind clouds, Vega and Altair as it is at the moment. With a dob you can hop from place to place, obvious maybe but never dawned on me before, so now I am Dobbing with a EQ mount.

Clear sky on the way.

alan.

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Thanks for replies. It seems that cost is a big factor which of course I accept. As I said I have the same OTA on both set ups and was expressing opinions from my experience. Perhaps if my home made Dob base was a bit more "user friendly" I'd appreciate some of the handling advantages.

(Sorry if the post seemed divisive, that certainly was not my intention)

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What design have you used for your DIY dob mount ?

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This is a really interesting thread and I think sums up the pros and cons very well. My own personal experience from using eq (Goto and manual) and altaz (including dob) is that I get a get deal of enjoyment regardless of mount.

The big argument for dob is the "bang for your buck" and ease of setting up.

I've noticed a couple of people saying how awkward Dobs can be with eyepiece position. I use an adjustable height seat when observing with mine and experience no discomfort at all.

There are thousands of accessories available to help us pursue our interest but an adjustable chair is fairly high up my list of essentials.

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