Switching to a Dob

[Graeme]

My cheap 114mm reflector is in need of replacement and I’m hoping to move up to a 200mm.

I’m used to an equatorial mount and it’s possible to get a 200mm on an EQ5 for a shade under £400 (200P EQ5) as suggested elsewhere on here but that’s a bit over my budget.

An alternative would be to switch to a Dobsonian mount like this (200P Dobsonian) for around £270.

As I’ve never had a go of a Dobsonian telescope so I’m not sure how they’re controlled. In the pictures there appears to be no part of the scope set up to point at Polaris and no knob to turn to keep up with the Earth’s rotation!

Could anyone tell me, how Dobsonians are controlled and what are the pros and cons?

Thanks

Regards

Graeme

[LukeSkywatcher]

Dobs are purely manual (unless you buy a Go-To version).

You really need to know your way around the night sky to use them.

Pros:

More light gathering ability (bigger aperture) at a cheaper cost

Cons:

No electronics involved so you so you do need to know exactly where to point them.

[Tiddles]

Dobs are purely manual (unless you buy a Go-To version).

You really need to know your way around the night sky to use them.

Pros:

More light gathering ability (bigger aperture) at a cheaper cost

Cons:

No electronics involved so you so you do need to know exactly where to point them.

Cons.....That's a big plus, no batteries, motors or electronics to worry about. The Dob is controlled by manual alignment with the object you are looking for.

Tracking......PAH.....gentle nudges keep it in the field of view.

It seems clumsy at first but soon becomes second nature.

[Bart]

Graeme,

I upgraded from a 150mm newt on an Eq mount to a 250mm Dob. I was concerned, just as you were, that I couldn't just turn a knob to keep the object in the FOV. I can assure you that it is a piece of cake. It becomes second nature in no time at all, and it is a lot easier to use, no more contortionist poses to get to the EP. Unless you plan to get into AP, the Dobs your man!

Do not worry. They are childsplay to use. I even built a home made Dob base to use my 150mm. The Eq mount is gathering dust and I'm open to offers for it!

Bart

[stevetynant]

Easy to transport - Easy to store - Easy to set up and get going - easy to customise (adding a setting circle and buying a wixey cost under £30 - manual goto genius) just get one or at least try and get along to a local society or astro meet and try one out you won't regret it

[squashnut72]

I just got a 150P Dob as my first scope and have found it very easy to use so far.

Putting it together is childs-play if you are OK with Ikea furniture and all you need to do to set it up before viewing is plonk it outside to cool down for half an hour.

You will find that you learn the sky quite quickly especially if you use phone apps to help identify what you are looking at.

Cheers

[Graeme]

Thanks everyone for the input.

I’ve been looking at and reading about the night sky for a couple of years now and know my way about fairly well, although I know it’s a lifetime of learning! I’ve never really been fussed about electronic goto but that’s probably just because I can’t afford it!

If gentle nudges are all that’s required that’s not much harder than twisting a knob on the EQ mount.

I don’t seem to have trouble with contortionist poses with the EQ because I can loosen the tube and rotate it where required to get the eye piece at chair level. This doesn’t look possible with the dob. I was hoping to further my so far extremely poor efforts at astro photography and assumed that I could layer short exposures thus rendering the auto tracking function unnecessary. Do I need motors to take photos?

Easy to transport, certainly looks like it. My 114mm tube doesn’t easily detach from the mount so I have to carry the whole thing together. The flexi tube ones look even better but I can’t find a 200mm manual version. The idea of customising it appeals to the engineer in me! Is the idea of retro fitting motors to make it auto tracking doable?

I’ll be ok putting it together and I have a few phone apps to help out with using it. Wouldn’t be without them! I use Google Sky Map, the excellent WhereIsIt and Planets Position.

Graeme

[stevetynant]

check skeye out aswel Graham I find that really good

[Daniel-K]

i sold all my stuff to buy a big DOB very pleased i did!

[benjii]

Don't forget you can convert your dob into a push-to if you want that added ease of finding things.

[tsmith001]

Hi

I have just bought a 200p dobby.

I am a newbie and armed with "turn left at orion" I have found the experience of a 200p worthwhile.

I reviewed loads of possible scopes before i chose the dobby and as a newbie i can honestly say i made the right choice.

It really is easy to set up and use and yes you have to nudge it to view the planets but after a while that is really straightforward.

I have to admit having a goto would be a luxury but if you dont want to spend the cash the 200p is a cost effective way forward

[rory]

" I was hoping to further my so far extremely poor efforts at astro photography and assumed that I could layer short exposures thus rendering the auto tracking function unnecessary. Do I need motors to take photos?"

dobsonians are not generally recomended for astrophotography.you'd want to stick with an g.e.m .

[stevetynant]

Hi

I have just bought a 200p dobby.

I have to admit having a goto would be a luxury but if you dont want to spend the cash the 200p is a cost effective way forward

make yourself a setting circle - buy a Wixey @ £25 and you have a push to system - poor mans goto but works fantastically well

[Eastridge]

I went from a 114mm to 250 DOb and I love the Dob. I find it easier to use and the nudging isn't an issue at all. Even after 6 years with the old scope I used to get frustrated finding things and would give up and leave it to hubby but with the Dob / Turn Left at orion & SKeye on phone (gives push- to) it's much easier and I love doing it myself.

BUT if you are going to want to photo anything other than moon / planets I'd head the warnings and consider another mount type.

[Graeme]

It would seem that the Dobsonium is the overwhelming winner then! Where’s all the EQ mount fans? The only exception being for astro photography.

Does anyone have any experience of using an auto tracking Dobsonium for astro photography? And can anyone explain why an auto EQ can take good photos and an auto dob mount can’t?

All things considered I’m going to go for a 200mm Dobsonium. I fancy a collapsible tube type but I can’t find a manual one for sale. The goto ones are £730.00 so that’s not an option. The auto tracking ones are £500.00 which is a bit over budget bit worth the stretch I think. I had best go and be really nice to the missus now!

Thanks for everyone's input to my decision making.

Graeme

[Daniel-K]

forget the auto tracking and get a 10inch and bit left over for a telrad no seriously the 200p auto tracking ones are great my friend had one and saturn would stay in the EP for an hour easy im sure you could do web cam imaging on the brighter planets and the moon too with them

[knobby]

Dob's are alt. AZ so even though it can track planets it doesn't rotate in an arc. Rather goes ' up a bit, right a bit, up a bit, right a bit ' ... whereas eq. Mounts follow the sky round ...

[Graeme]

check skeye out aswel Graham I find that really good

Downloaded! Looks good. Thanks

[Jon Sales]

Think I'll be going for a 10" Dob too.

Can't afford what I'd really like at the moment coz works been a bit thin on the ground but miss looking through a big scope so I'll get one in a few weeks time now with is starting to pick up a bit.

[Tiddles]

You can take pictures with a manual dob, just don't expect miracles.

saturn 2.bmp