Why Dob?

[barkis]

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

A simple modification to permit the OTA to be rotated in its cradle will solve the awkward eyepiece position problem. Not difficult to achieve either.

Tube rings to prevent tube slippage at higher altitudes.

Add to that, a height adjustable seat, and you may be able to remain seated all through your observing sessions

[Mak the Night]

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 don't get it either. There is an old joke on astronomy forums that the standard answer the 'Dob Mob' give to any telescope size or type enquiry is 'An 18" Dob!' lol. Disability essentially precludes my using a Dob although I think the concept of a Dobsonian telescope is an interesting idea. It does fascinate me how Dobsonian users often don't seem to understand that there are many who just don't like or don't get on with Dobsonian mounts. Different strokes for different folks I say.

[alan potts]

Jason,

Alan was joking, but I am not a member of the Dob squad.

Alan

[alan potts]

Mak the Night.

Sorry you are unable to use a Dob. I have I think most types of telescope and I know it is a preference thing but I would have saved myself a massive amount of money if I would have gone Dob at the start as I really enjoy these scopes. Yes I still use the 12 inch Meade, in some ways it is better than the Dobsonian even though much smaller but comes into it's own on planets, this is when I like a driven scope. I am using the 190mm M/N at the moment and it seems to be able to redirect clouds to where I am looking

[Beulah]

Jason,

Alan was joking, but I am not a member of the Dob squad.

Alan

What qualifies as a member of the Dob Squad, then?

[jetstream]

A simple modification to permit the OTA to be rotated in its cradle will solve the awkward eyepiece position problem. Not difficult to achieve either.

Tube rings to prevent tube slippage at higher altitudes.

Add to that, a height adjustable seat, and you may be able to remain seated all through your observing sessions

Great point Barkis. The nice thing about OOUK VX dobs is the ability to turn the tube in it's rings to make the scope fit the observer as well as adjust it for balance.

[Mak the Night]

Mak the Night.

Sorry you are unable to use a Dob. I have I think most types of telescope and I know it is a preference thing but I would have saved myself a massive amount of money if I would have gone Dob at the start as I really enjoy these scopes. Yes I still use the 12 inch Meade, in some ways it is better than the Dobsonian even though much smaller but comes into it's own on planets, this is when I like a driven scope. I am using the 190mm M/N at the moment and it seems to be able to redirect clouds to where I am looking

Before I had my brain bleed I always had an ambition to build a giant Dob, but the brain damage brought me to my senses lol. Ostensibly, a Dobsonian is a very clever idea for an inexpensive large aperture telescope. My next scope, which I hope to acquire relatively soon, will be a 235mm SCT with an alt-az GOTO. 

Failing that I may try and make DIY space rocket as it's the only way I think I'll get above the clouds at present. Once I'm in low Earth orbit a 4" Mak should be plenty big enough! 

[Mak the Night]

What qualifies as a member of the Dob Squad, then?

I have one of these: http://www.firstlightoptics.com/heritage/skywatcher-heritage-76-mini-dobsonian.html

I think technically that qualifies me lol.

[Beulah]

Great point Barkis. The nice thing about OOUK VX dobs is the ability to turn the tube in it's rings to make the scope fit the observer as well as adjust it for balance.

Can't do it with a Skywatcher. Potentially, the alt bearings could be removed and re-positioned but would require a bit of handiwork/drilling several holes in the OTA.

Managed to move the Finder scope below the focuser on the 16" dob, as it felt like I could fall into the OTA any second and be lost to mankind

Didn't have the right drill bit; it took a bit of work...

[estwing]

Jason,

Alan was joking, but I am not a member of the Dob squad.

Alan

oh yes you are...

[jason.p]

What design have you used for your DIY dob mount ?

My own design from scraps i had around the workshop. The idea was to make a dob base for zero cost. I posted an account of it a year or so back, but so far haven't been able to find. I'm going to attempt to attach a pic if i can remember how.

(sorry, couldn't attach pic. Completely different on this new tab. I'll keep trying)

[alan potts]

What qualifies as a member of the Dob Squad, then?

I am lead to believe it is a need to know basis, and I have never been informed, dark forces at play here I am sure . 

[jetstream]

The dob should definitely fit, mod Moonshane has made great bases and bearings for dobs and member greglloyd uses an OOUK base/rings that looks perfect. My truss dob works great sitting or standing (near zenith) and this was a primary concern when picking things out. The EP angle just seems to work.

I like all scopes but a well fitting dob is so stable and easy to use...

[faulksy]

Sorry to hear you feel like this.

maybe you read that wrong, alan wasnt knocking you, what he is trying to say is that a dob will do everything and a lot more than any other scope, except for ap of course

[jason.p]

My own design from scraps i had around the workshop. The idea was to make a dob base for zero cost. I posted an account of it a year or so back, but so far haven't been able to find. I'm going to attempt to attach a pic if i can remember how.

(sorry, couldn't attach pic. Completely different on this new tab. I'll keep trying)

Can someone please explain how I post a link to a previous thread. I've found it but don't seem to be able to copy and paste it.

The number is 197987. 26th Oct 2013

Thanks

[John]

... a well fitting dob is so stable ....

I think thats another benefit of the design that is underplayed I feel.

My 12" dob has pretty good optics so I find high magnifications often useable when the seeing conditions cooperate. The ability of the simple dob mount to handle 300x, 400x or more while retaining really good stability and fast vibration dampening never ceases to amaze me, even with the nudging to track a target at this magnification.

With equatorial mounts I would need to substantially overmount the scope to achieve this stability and that would require an equatorial mount of at least an EQ6 capacity mounted on a solid pier. Retaining any sort of portability would require more, probably something like an EQ8 or perhaps a Losmandy G11 ?

[John]

Can someone please explain how I post a link to a previous thread. I've found it but don't seem to be able to copy and paste it.

The number is 197987. 26th Oct 2013

Thanks

You can just cut and paste the url of the thread into your post.

[Moonshane]

For me it's about comfort when viewing and stability of image. In my experience dobs win on both counts.

[jason.p]

http://stargazerslounge.com/topic/197987-my-zero-cost-dob-base/

(Thanks Jo​hn. Still finding my way round a new tab!)

​

[jetstream]

The only thing about your base is that it may get in the way, and that brace might limit how far you can position the tube for balance. The bearings are on the small side for use with no friction brake. These are not negative criticisms btw, just trying to say what might cause observing issues.

OOUK's tube can be turned in the rings in seconds, no fuss at all. If you can make that base, you can make one like Moonshanes, not sure if the pictures of them are still on here.

At times I sit "under the dob" with my legs under the front of the tube, there are a lot of good observing positions with these things.

[Size9Hex]

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?

Great topic.

A few thoughts as someone who's new to the hobby, having chosen a Dob, and having never used an EQ mount (just to be open about my experience, or lack of).

For me, the optics would not have been the same; I could not have justified paying for such a capable scope plus (as far as I'm aware) an expensive EQ mount. While choosing, I also read more than a few posts stating that beginners might be put off by a more complex and less intuitive EQ mount. Maybe this was Dob Squad propaganda though ;-)

Either way, I chose a Dob, with no regrets so far.

Since choosing, I find I move the scope around the garden a few times per session to find targets in gaps between houses/trees etc. I'd guess this might be a faff if I was repeatedly re-setting an EQ mount? From this point of view, "once the scope is set up" is something that might happen a few times per session.

As I've never used an EQ, it's not possible for me to have a preference, but having found a Dob being cheap and simple, what would be the plus points (other than imaging) that would lead to someone favouring an EQ mount?

[DaveS]

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 ...

For example £400 ish 10" Dob (mostly money spent on mirrors) Orion neb superbly detailed and impressive .

Or maybe £400 ish 4se (mainly mount and a bit on mirror) Orion neb, faint wispy but recognisable

Or a 80mm ED and camera and see all the lovely colours and details, not just a greenish-grey smudge.   

[John]

Or a 80mm ED and camera and see all the lovely colours and details, not just a greenish-grey smudge.   

And an equatorial mount ?

[Mak the Night]

Or maybe £400 ish 4se (mainly mount and a bit on mirror) Orion neb, faint wispy but recognisable

I disagree wholeheartedly. I have a 102mm (4") Mak and M42 was neither faint nor wispy when I observed it at 130x a few nights ago. Admittedly I was using a 10mm Delos and I live in the greenbelt.

[DaveS]

And an equatorial mount ?

Oh, for sure. But you could get away with an HEQ5 or even an EQ5 at a push.

TBH all my serious 'scopes have been eq mounted, and when I was using my Meg 90 visually I prefered to keep my hands well away from it.