what are the weak points/limitations of a dobsonian?

[appy]

As title

thanks

[Qualia]

This page might help with your enquiry: Selecting a Telescope

[appy]

Thanks

I was all set to get a Skywatcher Skyliner 200 Dobsonian until today when someone said they are no good for looking at planets just dso's???

[appy]

arrhh makes sense now

[appy]

"sigh" back to the drawing board......

[LukeSkywatcher]

Thanks

I was all set to get a Skywatcher Skyliner 200 Dobsonian until today when someone said they are no good for looking at planets just dso's???

Not strictly true. A 200mmm Dob will deliver on both.

[perrin6]

You can't do photography with them except of a very limited kind

If you like fiddling with techie stuff and whirring noises, dobs are not for you

If you like spending loads of cash dobs are not for you,

errrmmmm that's it (unless you want to compare newtonian reflectors with: refractors, shmidt-cassegrains & maksutovs in which case the answers will be slightly different from the above)

[ronin]

You can use a dobsonian on planets, you can use a long refracor on DSO's. One may be better suited to the particular job then the other but it is a matter of degree.

Dobsonians are often short focal length so may not take high magnifications, planets are illuminated, have a size and so using high magnification is possible and useful.

As a Dobsonian is basically a mirror there is just one surface to grind so they are less expensive to produce, for a similar cost you get a bigger mirror then a lens. Bigger mirror means more light so you see a DSO a bit brighter.

What do you do with say a 150PL, dobsonian and a longer focal length so you can get higher magnifications.

Which ever bit of equipment, Dob, Refractor, Mak, SCT, you choose it will be better suited to one thing then it is to another.

[ismangil]

Last night here on SGL7 I viewed 4 planets here on my 200mm f6 Dobsonian, up to 200x magnification I can still nudge to follow it.

Also glimpsed M51 and it's companion galaxy.

So there you go, planets and DSO

Perry on mobile (so blame strange words on text prediction!)

[Macavity]

On a basic Dobsonian (or any manual mount) I would mostly miss the "tracking" aspect. I really like the possibility of taking a fair break from the eyepiece and returning to find objects still in view. But Dobsonian mounts now come with motor drives too...

One person's desirable convenience is another's unnecessary complexity though?

[swamp thing]

Hi

TBH the only limitation I've found is if you wish to do deep sky Astro imaging.

Or as Macavity said if you wanna go make a brew in the middle of observing an object (must admit I miss that a bit too)

Every thing else is do-able with a Dob mount.

The thing I always find amazing when I use any other mount is how much more stable a Dob mount is. Even huge heavy EQ,s struggle to match the stability of a few bits of ply.

Regards Steve

[knobby]

On a basic Dobsonian (or any manual mount) I would mostly miss the "tracking" aspect. I really like the possibility of taking a fair break from the eyepiece and returning to find objects still in view. But Dobsonian mounts now come with motor drives too...

One person's desirable convenience is another's unnecessary complexity though?

I find that its great fun to try to pre-empt the movement, I try to guess where my target planet will be in 3 minutes time, quickly make a brew and rush back to see how far out i was !

you just can't have that much fun with a goto

[appy]

all good points thanks peeps, im just worried ill spend the best part of £300 wrongly. The problem with the internet is one site says one thing and another site says the opposite. Going to a mates tonight who has borrowed a couple of different scopes for me to try

[knobby]

What scopes, do you know ?

[Macavity]

I try to guess where my target planet will be in 3 minutes time, quickly make a brew...

Or, if the cold nights get to you, the obligatory "rest room" break?

Aside: Most telescopes will do most things... to SOME approximation. Never say never! It's unfortunate that none will do everything perfectly. Not a Dob Man... Can't "do weights", these days. But one has to go for SOME sort of scope, initially. If you're (physically) fit-ish, of reasonable patience, an 8" manual Dob would not be a huge mistake as a first (general) step. Better than many of us had?

[mik]

:evil6:The only fault i know of is they have mirrors:evil6:

[twotter]

A better question might be 'what are the possibilities with a dobsonian'?

Answer: for visual use, endless

My SW 200P dob has given me great views of the Moon, Jupiter, Saturn, Mars, Venus, even a look at Uranus too. Then so many DSOs, double stars, clusters, galaxies and nebulae. It's so simple, quick and convenient to use I may never need another telescope

[knobby]

:evil6:The only fault i know of is they have mirrors:evil6:

hang on a minute while i reflect on that statement ...

[littlebeagle]

Astrophotography is probably the main weakness, but with an auto tracking one, webcam photography is still possible.

I've got some good shots of Jupiter so far with mine, waiting to do one of Saturn now.

[4lefts]

someone said they are no good for looking at planets just dso's???

just to echo what others have said - this is like telling someone "don't buy a car, they're no good for carrying things, only people, get a van".

you can get great views of planets with a dob.

[tony4563]

Seconded

[UnderTheRain]

For viewing dobs are nice and easy, quick to setup and easy to use and you can use them for anything although some dso's might be very faint depending upon the size of the scope so make sure you have realistic expectations of what it is you're going see. If you want to use a web cam and image planets likewise they can be very effective. The only real drawback is if you want to image dso's they're not very useful for long exposure photography. You might be able with a perfect setup to get 2 min exposures which for long exposures might not be long enough.

I have a 10" newt and I'm seriously considering making a dob base for it just so I can pop it out side quickly for viewing. Setting up the eq6 for imaging is fine but it doesnt make for a quick grab and go by any means where as the dob would be sooo much quicker.

UTR

[kenmyers]

I have newts and eq mounts but honestly I mainly just plonk it outside and point it straight at my target and deal with the controls from there... occasionally I will polar align to just use the one control but its not really that important at all for just observing.

I am glad I don't have a dobsonian mount for it though, having the eq mount is very usefull for tracking manually instead of nudging as it is much more smooth. I can also undo the locks on ra and dec, flip the lattitude, and I have a dob mount. I can also correctly align and add a ra tracking motor and use it for astrophotography. eq mounts are very versatile.

[Moonshane]

assuming the base is well constructed and adjusted a dob mount will provide a very stable base which can easily be used for all targets and at high magnifications. I have been observing Mars at up to 300x tonight with no issues.

at larger apertures the bases of commercially made dobs (which is what I presume you are referring to) can be heavy and very large. tubes up to 10" are quite light and easily mounted.

12" and larger tubes can be quite heavy, bulky and large

as mentioned dobs ae not really good with imaging and can be tricky on very uneven ground.

other than this dobs generally offer the best value for money, stability and aperture which all means more satisfying visual images per £ compared with other systems.