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DOB mounts versus Equatorial

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#1 ve1drg

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Posted 18 October 2013 - 01:41 PM

I have never used a DOB mount telescope but only the equatorial types. I was wondering just how these DOB mounts compare to the other mounts?
At present I have a SkyWatcher AZEQ6 mount and it is wonderful. But of course it won't take anything that large in size. So if I wanted to go to a large scope it looks like the DOB arrangement is the way to go.
Are people happy with these mounts or are they 'longing' to get back their normal Equatorial mounts..
:smirk:

#2 Jon Isaacs

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Posted 18 October 2013 - 03:09 PM

I have never used a DOB mount telescope but only the equatorial types. I was wondering just how these DOB mounts compare to the other mounts?
At present I have a SkyWatcher AZEQ6 mount and it is wonderful. But of course it won't take anything that large in size. So if I wanted to go to a large scope it looks like the DOB arrangement is the way to go.
Are people happy with these mounts or are they 'longing' to get back their normal Equatorial mounts..
:smirk:


I have recently gifted my various equatorially mounted Newtonians on to others, I just was not using them. I am a Dob guy. Dobs are just so much simpler and smaller. A 12 inch Dob, is a easily managed scope, a 12 inch on an equatorial mount is a quite a chore.

I do have a equatorial platform in case I really want the tracking but I am do it myself sort of guy so I am pretty fine with hand tracking.

Jon

#3 hbanich

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Posted 18 October 2013 - 03:16 PM

Hi Ted,

Dobs are popular for good reasons, but it's difficult to say what percentage of Dob users long for tracking. For myself, I went from a German equatorial mount on my 8 inch f4 to a Dob mount years ago and loved the change because of portability and ease of use. Tracking would have been nice, but 25 years later I haven't done anything about it, probably because I primarily use this scope for low power, wide angle viewing.

On my larger scopes I've either built equatorial platforms or installed an alt-az drive, both of which work well. I value tracking for these larger scopes because I frequently use them at high powers for extended periods of time.

So in my case the value of tracking depends on how I use my scopes. A Dob with smooth movements is a joy to use, and as a recent thread on CN has shown, there are some folks who prefer the simplicity of hand tracking a Dob.

#4 Stelios

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Posted 18 October 2013 - 03:52 PM

I don't think that equatorially mounted Newtonians are at all popular today. People who want tracking usually get refractors, Cats (SCTs, Maks, RC's, DK's), or, if they can afford them and are not into AP, tracking DOBs.

People who don't care for tracking usually get a grab-n-go APO, or a DOB depending on whether they care most for pinpoint stars and/or wide fields or hunting DSO's.

And then there are those who want all three--a grab-n-go, a tracking scope (usually for AP, but sometimes for high-power visual) and a big DOB light-bucket.

IMO, whether you'll be happy with a DOB depends very much on what type of observing you do, and whether you enjoy finding things in the sky as well as observing them. I know I would get very frustrated with a DOB *unless* it had tracking and GoTo. But others totally love them, and for bang-for-the-buck they can't really be beat. The darker your skies, the more (IMO) you'll like a DOB.

#5 Jeff Morgan

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Posted 18 October 2013 - 03:53 PM

For those that want Dob tracking solutions, they are there. Some of them can be had for less than the cost of a couple of premium eyepieces.

But getting back to the base comparison, only in the case of imaging do you give up anything at all. Oh, one other item - if you star hop it is a bit easier equatorially because the mount motions match the North-South-East-West of your charts.

Since the Dob does not have a tipped axis, the scope center of gravity can be centered over the mount. You just can't beat that for stability. You can equal it - with greatly increased requirements in materials, mass, and cost.

#6 GeneT

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Posted 18 October 2013 - 04:41 PM

Dob mounts and hand tracking work quite well, especially with eyepieces 82-100 AFOV. I own a Tom O Equatorial Platform, but don't use it half the time.

#7 tomcody

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Posted 18 October 2013 - 05:11 PM

I think the real question is if you can be happy pushing the mount to keep the target in view? can you spend time at the eyepiece without having to stand up and stretch (say for a sore back problem?). On a personal note, after twenty five years of tracking mounts, I tried a push to and found my health would not allow that much time at the eyepiece without breaks and every time I took a short ( a few seconds to straighten my back) the target would be gone and I have to find it again. You may want to try shutting off your tracking ( a somewhat unfair test as a dob would have better& smoother hand control than your present mount with the drive off ) and see if it works for you. If not? a tracking dob may be what you want/need?
Rex

#8 Eddgie

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Posted 18 October 2013 - 05:16 PM

I have an Orion Go-To dob.

This model has (as compared to a similar non Go-To dob) a very heavy base which is a bit negative.

But I can keep mine on my covered patio and roll it out with a hand truck very easily.

It has Go-To, and it can also be pushed too (the design has two sets of encoders so you don't loose position by pushing the say most Go-To GEMS do).

So, I get Go-To and Tracking and can run several hours on a simple battery pack of 10 AA Eneloop 2500ma batteries, or for a very long time on a 7 Ah battery.

The other advantage of the Go-to dob is no more balance issues.

I can go from a 12mm Ortho to a 1.7x GPC, Mark V binoviewer, and two 13mm Hyperions and not have to rebalance. In fact, I don't even have to worry about the scope moving while making the change. It is very solid. I can swap eyepieces in the binoviewer and never have the target shift in the field.

I love the Go-To dob. I miss the slightly better DSO performance of the C14, but I now get a much wider field of view, and the tradeoff has worked well for me.

And for about $1100, you can get a small Go-To dob, and for about $2200, you can get a 12" Go-to dob.

This is less than the cost of a GEM for a C11.


If you have a garage or shed, or even a covered patio where you can keep the dob, Go-to or non Go-To, it makes it very easy get observing quickly.

Oh, and it gets better.

With Sky Safari, you can wirelessly control your Go-To dob with an Iphone, Ipad, or Android tablet. How cool is that!

Even without Wireless, I can sit there with the Andriod tablet and knock out target after target after target in a two or three hour session.

Go-to just makes you far more efficient, and to me, far less hassle than with a standard push to dob.

Loving my XX12G.

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#9 esd726

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Posted 18 October 2013 - 06:14 PM

Love observing with a Dob. I don't like EQ mounts at all. The awkward positions, the IMO relative difficulty in moving from one side of sky to the other, etc. The only thing I liked about a EQ is IF you polar align you can track. I only liked that at higher power anyway...so. For ME it's NO to the EQ :cool:

#10 Erik Bakker

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Posted 19 October 2013 - 04:25 AM

A well-made dob-mount is a wonderful thing. Nothing beats it for sailing the heavens at low to medium powers. I also use mine happily while binoviewing at 200-270x, but miss the driven equatorial at powers 300x and above. An equatorial platform could take care of that. In my climate, I find myself using powers between 100x and 220x most often, so I really enjoy the simplicity, compactness and featherweight of my 16" Dob: it has roughly the same weight and bulk as my 4" (!!!) equatorially mounted APO.

#11 Astrojensen

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Posted 19 October 2013 - 04:36 AM

Are people happy with these mounts or are they 'longing' to get back their normal Equatorial mounts..



I use both and effortlessly change between them. I use equatorials for my refractors and have a 12" f/5 dob, which is almost the perfect combo of scopes and capabilities. The 12" is a Meade Lightbridge and it's pretty good straight out of the box, with good, smooth tracking, allowing easy hand tracking at up to at least 340x, which I use once in a while, although it must be added that I use 82° and 100° eyepieces on it, which significantly eases manual tracking.


Clear skies!
Thomas, Denmark

#12 obin robinson

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Posted 19 October 2013 - 08:07 AM

I have never used a DOB mount telescope but only the equatorial types. I was wondering just how these DOB mounts compare to the other mounts?


This is like comparing apples to oranges. These are two different mounts for two different kinds of users. Do you need tracking, or you need to find objects via RA and DEC? Do you need the ability to find via ALT and AZ? Do you do astrophotography? This is like asking how many people have gone from a sports car to a truck. The answers are going to depend on the needs of the individual person and don't have a relation to the equipment itself.

obin :confused:

#13 tomcody

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Posted 19 October 2013 - 09:20 AM

Ted,
You should try a dob before deciding, the Chiefland Fall star party is starting on the 28th of this month. (google it for info). and it is only about a three hour drive from you. Perhaps you could attend for even a day? and I am sure there a number of people there who would show you their dobs and you would learn real quick if one is for you.
Hope to see you there.
Rex

#14 Dick Jacobson

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Posted 19 October 2013 - 12:45 PM

It is possible to build equatorial mounts for large Newtonians that are only slightly larger and heavier than a Dob. Unfortunately, I don't know of any that are available commercially. The split-ring equatorial 12.5" and 18" scopes from JMI are the closest that I know of.

Pictured below is the 14" that I built recently. I have also built successful equatorial mounts for 10" and 20" Newtonians. I greatly prefer them to Dobs because of easy tracking with or without a drive, easy polar alignment, natural north-south-east-west motion, and no "Dobson's Hole" (awkward motion near the zenith). A rotating tube or eyepiece section is just about a necessity with an equatorial, but once you have it, it is more comfortable to use than a Dob.

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#15 ve1drg

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Posted 19 October 2013 - 12:58 PM

Thanks for the tip. I might just do that. I have seen these DOBS around but never used one. However I am thinking that if I go to a large scope - it will have to be something like a Dob..

Cheers.

#16 starbux

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Posted 23 October 2013 - 11:54 AM

Would I be correct in concluding that the secondary in the telescope rotates in various click-stop positions?

#17 csrlice12

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Posted 23 October 2013 - 12:28 PM

You could use a stationary secondary and rotate the outer eyepiece section. Maybe have a spring loaded notch to line it up right.

#18 Dick Jacobson

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Posted 23 October 2013 - 03:08 PM

Would I be correct in concluding that the secondary in the telescope rotates in various click-stop positions?

No, the secondary mirror is fixed and the cage rotates around it so I can switch eyepieces just by rotating the outer cage. There is a click-stop mechanism. See Seven focusers on one telescope






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