Choice between nudging a dob around or using a manual EQ mount for tracking
G'day,
I'm looking around for my first scope and seem to have come down to a choice between either a:
- Skywatcher 8 inch newtonian on an EQ5 manual mount
or
- Skywatcher 10 inch collapsible dobsonian
Both a similarly priced.
Yes, the 10 inch aperature of the collapsible dob sounds inviting, however I'm worried that I'll very quickly get frustrated at having to continually nudge the scope to keep objects in the middle of the field of view. The 8 inch on the manual EQ5 mount should make this issue a lot easier to work through, though at the cost of aperature.
So, can I perhaps hear people's experiences of using a big phat dob to track objects and how annoying it can be to keep nudging the beast along?Perhaps it ain't that hard?
My idea of getting a manual EQ mount is that I can find my way around the sky, and, If I need to, pause to consult my star charts, then go back to the scope to continue the star hopping. An EQ tracking mount would allow me to quickly catch up where I left off. My concern is that with a dob it would be harder to take up where you left off, because there would be 2 axis' to correct and you'd get lost a lot easier.
My hair is falling out over this. Can anyone help me?
Cheers!
Last edited by Mountain_Wanderer; 27-09-2010 at 08:41 PM.
For visual, I would go for the 10" for future Astro Photography I would go for the EQ.
When I first joined I really didn't know what I wanted so I went for the DOB for budget and apeture. I am fortunate enough now that I can do photography after making an EQ platform which I am considering making for others when I have refined the process.
I must admit fisr time choices can be hard, if I joined an astro society in the first place then my selection would have matched what I initially mentioned.
Personally I have never found nudging a dob to be at all frustrating. It is quite a natural movement. To my mind, much quicker to get used to than setting up an EQ mount. Setting up an EQ does get easier with practice, but it seems to me that it would always take longer than setting up a dob.
You will get good at nudging the dob in no time Jowel. Good quality widefield eyepieces in your two most used focal lengths (10mm & 25mm) will help you no end, as the object will take longer to travel across the fov, so you won't need to nudge the dob as much. Just to note as well, the planets move across the fov a lot quicker than deep sky objects. I also use a Red Dot Finder, so if I lose things I can find them back much easier.
How about getting the 10" for now and adding an Argo Narvis down the track. Best of of both worlds .
All this said and done Jowel, I think you pretty much answered your own question when you expressed that you may get frustrated nudging the dob. This hobby takes quite a bit of perseverance & patience. If we don't have it to begin with, we end up acquiring it.
Have you looked into how much setting up an EQ mount involves? I just know that when I want to quickly get out there for a short session, my dob is ready to go at a whim. Drag it outside 30mins- 1hr before observing (to cool down) and that's it. When I'm finished, there's no packing up, I just drag it back in.
You've just got ask yourself what is going to be less of chore for you - setting up EQ mount or nudging a dob. The reason I went for a dob is because, I knew I lacked the patience to set up a mount and because of that, I was worried as to how often I would actually feel motivated to set it up everytime I wanted to use it. I now actually enjoy nudging the dob - I feel in control of my vehicle. Zoom zoom.
Nudging a dob will only be part of learning patience & tolerance... you then have targets to find as well... Though frustrating at times doing it manually, it is highly challenging and rewarding.
Depends on what you're after. If you're into visual and want the biggest scope you can afford/handle, go for the dob and learn to track manually. Eventually it'll be second nature, like driving a manual car . You'll want smooth motions, as a jerky dob will create mass quantities of frustration. Not sure how the SW dobs fare in this department. You could get an EQ platform, but these are fairly pricey.
An EQ mount will provide easier tracking, but take more time and effort to set up properly (bigger learning curve aswell!). But take note, that a Newt on an EQ mount will result in awkward eyepiece positions which will require rotating the tube to get the EP in an ergonomically comfortable postition as you swing it across the sky. EQ mounted Newts are generally not recommended for visual for this reason, but you can get a set of rotating rings which will allow you to rotate the tube within its cradle.
I'd say try before you buy. You could try buying either the dob or EQ second hand and give it a good workout, that way you could re-sell it without monetary loss if it doesn't suit you.
Dobs are great at low magnification of course. It's only when viewing planets at reasonably high powers that it becomes frustrating. So all jokes aside - It really does depend on what you want to do most of.
Dobs are great at low magnification of course. It's only when viewing planets at reasonably high powers that it becomes frustrating. So all jokes aside - It really does depend on what you want to do most of.
I will totally agree, without tracking DOB's are awful for closeup planetary, reasonable for wide moon. They are though great at high power when tracked.
I started out with a so called 'DOB' back in the 70's. Back then they were called ALT AZ mounts. Imagine a dob on a 3 legged, big lump of pipe 3' high. I think I was at it for 2 weeks before asking my dad if we could make an EQ mount, which we did. 2 weeks after building the EQ, it was "dad, we need a motor!"
Guys thanks so much for all this wonderful advice. It's a hard decision to make here. Either go for the 10" aperature over the 8". Or, go for a better tracking system (Eq) over the dob.
I'm trying to work out 2 key things here:
1. How much better is 10" over 8"? I hear that for planets, both are similar, but for deep sky objects the 10" is king. But then the 10 inch is bigger and harder to lug around and is only available in a dob mount. And I hear that the 8 inch can deliver a lot of good quality views and can do just about everything well.
2. Is a manual eq mount (non-motorised) much more better at tracking than a dob or is it only a marginal improvement and therefore not worth getting? I'd like to look at planets in high magnification. I'm worried that with a dob I'd be forced into using lower magnification and also the annoying problem of having to sharply shift the scope aong 2 axis to keep it in view. Would the eq mount allow me to magnify more and also provide a smooth movement of the scope to track planets? Though there's also the worry of how difficult it would be to align to the south pole every time I want to use it.
The temptation of larger aperature is there with the 10" but there seems to be a lot of concessions involved: larger, heavier, difficult tracking. Dunno whether I should fall for temptation or stick with the 8" which should do the job.
I know you want to do both but ulimately what do will you end up doing.
Planetary mostly - 8" with tracking.
But if you intend to do DSO mostly which there is a lot more to see then 10" is the way to go. If you can wait a bit longer to save the pennies then track as well.
Even though I do planetary mostly, I know I made the right choice for 12" as I know I will further down the track will observe more DSO. I will also purchace a heavy duty mount for the DOB in the future or build one. DOB tracking was not available when I bought my scope.
the beauty of a dob alt-az mount is that while you are moving it in 2 axes, you do this simultaneously ie you just grab the top of the scope with your paw and move it. Simple. I view at high power and move the dob and sketch. It becomes second nature and is quite intuitive. I find observing with a dob very easy and while it would be a little easier for sketching to track, it's really not that hard. And a 10" is not that much more effort to move than an 8". But I would say that setting up with a 10" dob would be considerably quicker and simpler than setting up an 8" on an EQ. Especially if each time you will have to polar align the scope, even roughly. It's quicker to set up my 16" dob than my ED80 on CG-4 EQ even though I have the tripod position marked.
I learnt on an Manual EQ mount and had an 8" newtonian on an Alt/Az base both have their good points and bad, if your after a reasonable GOTO but the simplicity of an Alt/az base for visual work, then the new computerised scopes from Skywatcher are ideal and a reasonably low cost. If you want to get into Astrophotography then a German Equatorial would be better. If you want to do live video then the Alt/az would be fine for that also. The choice is endless, I dont find the use of GOTO a problem infact most of the time you pick up where an object should be using GOTO, similar to star hopping, you eventually figure it out. One down side to an EQ mount for visual is the eyepiece tends to get in some weird and wonderful positions which can get quite awkward to get to. Hence the Alt/Az base as the eyepiece is usually at an place where you can get to it.
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,you should be taking more care with your pride and joy.
haha, I do actually drag it outside - she's on wheels, drag drag drag. 
