Dobsonian Mounts

[gareththegeek]

A few questions about Dobsonian mounts...

• Do you need to get the mount level?
  
• If so how is this achieved since the mount does not have tripod legs?
  
• Do you need to place the mount upon a surface such as table or do you just put it on the grass?
  
• What keeps the telescope from moving in its mount, does it have locks or is it just held in place by friction?
  
• Do these mounts have any fine control over rotation or do you simply push the telescope by hand?
  

Thanks,

G

[Doc]

A few questions about Dobsonian mounts...

• Do you need to get the mount level?
  
• If so how is this achieved since the mount does not have tripod legs?
  
• Do you need to place the mount upon a surface such as table or do you just put it on the grass?
  
• What keeps the telescope from moving in its mount, does it have locks or is it just held in place by friction?
  
• Do these mounts have any fine control over rotation or do you simply push the telescope by hand?
  

Thanks,

G

1. The more level it is the better it will move smoothly but it's not essential to have it dead level.

2. I've made adjusters for my dob so I can adjust the height by tightening the adjusters as I like a level scope as I have a push to go-to system on my dob and it needs to be level to work.

3. Depends on the size of your scope, if it's 8" or above I would just place it on the ground. Be careful about wet grass as the base board could warp if it gets wet.

4. Mainly friction, but they do have a altitude brake, I never use mine because if your scope is perfectly balanced there's no need for a brake.

5. No fine controls, just push or nudge to keep an object in view, once again if the scope is balanced correctly then this is easy to do.

Hope this helps.

[gareththegeek]

Yes, thanks.

I have been thinking of getting an Explorer 200P on a EQ5 but everyone always seems to recommend Dobs so was trying to work out how they work I think 8" is the largest aperture I can fit in the car and carry easily but I think I am still leaning in favour of buying an EQ mount atm.

[Doc]

There's a steep learning curve to the EQ mount where a dob is so simple a young child could use it without help.

[gareththegeek]

Indeed, but I think I would enjoy the learning curve I think in the long run I would get more out of the EQ mount. Is it possible to get the OTA on a Dob mount and then later attach it to an EQ mount?

[John]

Indeed, but I think I would enjoy the learning curve I think in the long run I would get more out of the EQ mount. Is it possible to get the OTA on a Dob mount and then later attach it to an EQ mount?

With the Skywatcher 8" dobsonian you can later get some tube rings and a dovetail for it and put it on an EQ mount. Another advantage (IMHO) with the SW 8" dob is that it's an F/6 rather than and F/5 as the EQ mounted 8" is. This makes it easier to collimate and keep in collimation, it's a bit more forgiving of low cost eyepieces and delivers slightly better contrast because the secondary is smaller with an F/6.

Unless you are really keen to get to grips with an EQ mount then I'd go for the dob every time. They are easier to move around and lighter than EQ mounted equivilents as well

[gareththegeek]

Yes, I noticed that the Dob version is f/6 not f/5 But also it is more expensive to buy the EQ5 by itself rather than with the OTA for some reason. I may never decide!

[John]

Yes, I noticed that the Dob version is f/6 not f/5 But also it is more expensive to buy the EQ5 by itself rather than with the OTA for some reason. I may never decide!

You can pick up EQ5 / CG5 mounts for £not much used to be honest but I can understand that you might want to get the whole thing sorted now. The 8" on the EQ5 mount is a very popular choice and rightly so but I just find EQ mounts a pain in the proverbial as they put the eyepiece in all sorts of odd positions which my old back does not appreciate !. If you are interested in imaging at some time though an EQ mount is a must really. I'm just a visual observer who prefers simplicity !.

[pvaz]

Dobs have mainly 3 advantages:

- Virtually no setup time

- Ease of use

- Price

If you keep a dob in a garage/shed and you have the conditions to observe at home, then from the time you decide to go out, till you have everything ready to observe takes only 1 or 2 minutes. No exaggeration! You just pick it up in 1 piece (if <=10") from the shed/garage, move it, put it down, remove the caps, and observe!

And to me thats the most important pro of a dob, it's a time saver.

PS-> Got nothing against EQs, but everything haves it's own pros and cons, and time/simplicity is a big plus for me. I do plan to add an EQ and a refractor to my gear, somewhere in the future.

[gareththegeek]

One thing that attracted me to getting a newtonian is (being fairly tall) that the eye pieces are at the top. With a dob mount won't the scope be fairly low to the ground when compared to an eq mount?

[pvaz]

Mine (8") is too low to stand, but just perfect with a chair beside it.

[LukeSkywatcher]

One thing that attracted me to getting a newtonian is (being fairly tall) that the eye pieces are at the top. With a dob mount won't the scope be fairly low to the ground when compared to an eq mount?

Sorry but i cant be of any help on this one because i have only ever used a refractor on an EQ mount and more recently my Dob. I am in a wheelchair so both types of mounts present different user experiences for me than they would for able-bodied users.

If anything my Dob is a bit too low to observe with it on ground level so i usually put it on top of a small step stool. I'm looking forward to the warmer months (ha ha ha) so i can sit on the grass in my garden with a blanket and observe without the stool.

[Chris H]

Dobs may look a bit basic but that is the beauty of them. You get them out, set them down in the garden and that's it. I only really use mine from home so I've set a 2ft square paving slab in the lawn its roughly level but not dead on and it keeps the base dry. I am well and truly a dob snob, I don't think I would ever go for any other kind of scope maybe just a bigger one.

My 10" fits quite easily in my car the tube goes across the back seat and the base in the passenger seat. As Paulo has said the 1200mm focul length tubes are a bit too low to stand and use, it is possible but far better to sit, relax and enjoy a steady view through the ep so highly recommend you budget for a chair.

[pvaz]

An image shows it better:

http://stargazerslounge.com/members-equipment-gallery/102482-me-my-dob.html#post1420819

[LukeSkywatcher]

Now thats observing in comfort. Kinda makes me wish i got a 8" Dob but then again it wouldnt be AS portable FOR ME as my 5" Dob.

P.S.~~~You might see better with that 8" Dob if you open the curtains.LOL.

[pvaz]

Now thats observing in comfort. Kinda makes me wish i got a 8" Dob but then again it wouldnt be AS portable FOR ME as my 5" Dob.

P.S.~~~You might see better with that 8" Dob if you open the curtains.LOL.

I'll give it a try and see how it goes!

[LukeSkywatcher]

I'll give it a try and see how it goes!

Don't feel bad about it. Its a besic error made by most newbies to the sport.

[pvaz]

Few, glad to know that! Thanks for the heads up!

[orionhunter]

its very true about the time factor. my SW 150p dob can be up and running within a minute or two.

very easy to transport too.

id only ever part with it for a bigger one. a 200 or maybe a 300.

ive also got a small SW refractor, and a SW helios on an EQ mount. all used equipment.

and some 20x50 binos.

lots of options, yet my total scope outlay is less than 300 quid.

[gareththegeek]

Sounds like a dob would be handy if you wanted to nip out into the garden at short notice. Problem I have is that my garden is on a slope. Not many level places to put a scope and hill obscures two horizons and my house a third so I can only really see things near the zenith or in the West. However I can imagine that an EQ mount would leave the eye piece at very awkward angles sometimes. You would think someone would invent tube rings that allow the OTA to rotate.

[Chris H]

I think that you have to leave your tube rings tight enough to hold but loose enough to rotate the tube to get the ep where you want it.

[russ]

They do make rotating tube rings but boy are they pricey. Antares did some for a while but even those were something like £150.

Sounds like you have a dilemma. EQ's become especially awkward to use around the zenith or pointing anywhere near pole. Suddenly it won't move the way you want it to, highly annoying.

I did have a dual mount setup for my 200P dob but have now completely given up on EQ's. It's now the dob and an AZ refractor. Both can be setup and used within 1min. That's from opening the shed to sitting at the eyepiece. It's simply not possible to have a faster setup time than a dob.

While i find it a breeze to use and now can't stand EQ mounts (not even for high powered planetary viewing), a few people at our dark sky site meeting found moving the dob intimidating. And too easy to lose the target object. But with practice it becomes second nature.

I use an ironing chair from Lidl's for observing at the dob. It's all very comfortable indeed.

[gareththegeek]

Presumably if I was using an EQ mount and wanted to set up quickly in the garden I can just plonk the thing down and not bother aligning it to the Polaris - just make sure its pretty much level and get on with it? Do the weights need adjusting all the time or do they tend to be ok between uses?

[russ]

For a quick visual look there's no need to anything other than plonk the EQ down with the mount very roughly pointing towards polaris. I never bothered with the polar scope, just a quick glance along the mount.

As you move from area of the sky to the next and flip the scope over, you made need to re-balance.

[gareththegeek]

For a quick visual look there's no need to anything other than plonk the EQ down with the mount very roughly pointing towards polaris. I never bothered with the polar scope, just a quick glance along the mount.

That's what I figured because ppl make out that setting up the EQ mount is a big production but I would think the amount of time you put into settings the mount up should be proportional to the amount of time you intend to use the scope for!

As you move from area of the sky to the next and flip the scope over, you made need to re-balance.

Can you elaborate on this? So the scope will not be balanced in all positions?