What can i see with a 10 or 12" Dob Zhumell?

[doat1]

Hello again everyone, i am planning on purchasing a 10 or 12" dobsonian zhumell telescope and would like to know what can i see with either of these? I would like to be able to see Saturn or venus or something of the sorts.

[Doc]

A dob with an aperture of 10 to 12" should make out all the planets. The whole Messier catalogue of 110 objects and loads more.

The globular and open clusters will look amazing as will the nebulas. Galaxies will still look like smudges except from a very dark site bull all these objects should be visible.

Take a look at my constellation list, most of these will be visible in your scope.

http://stargazerslounge.com/primers-tutorials/81493-object-list-indexed-constellation.html

Have fun.

[ollypenrice]

Hi,

From a dark site there are many fine nebulae you can see, too. When winter comes, Orion is wonderful - M42/43/ but forget the Horsehead. In the summer the Milky Way offers a host of targets. Do you have good star charts? Computers are not much use because they blind you!

Olly

[acey]

All the planets out to Saturn are bright and easily visible with the naked eye. Even a very small telescope will show Saturn's rings, the phases of Venus, and the moons of Jupiter - Galileo saw all of these with a 2-inch telescope. Any modern telescope will show you the same things in better detail, and you don't need huge aperture, you need good resolution and high contrast. A top-notch 4-inch refractor will outperform a low-cost 12-inch dob on planets. Also with a dob you have to keep pushing to hold the planet in view, which can be annoying at high power. So a dob isn't the perfect planet scope - though it is a very good "all round" scope if you also want to look at deep-sky objects (galaxies, nebulae, clusters).

With those, it all depends how dark your sky is. If you can see the Milky Way very clearly with the naked eye then 50mm binoculars will show you all the Messiers; a 12-inch scope will show all (or nearly all) the NGCs above your horizon - thousands of galaxies.

If you view from a typical suburban sky then you'll see a lot less, and might struggle even to find Messiers with a 12-inch.

Planetary views aren't seriously affected by light pollution - it's heat rising from buildings that causes more of a problem.

I think dobs are great and ideal as a first scope (and second, third, fourth...), but I'd suggest 8-inch as a good starting point. Don't just look at the cost, look at the size and weight. And think about what you want to look at. If it's just planets then a 100mm apochromatic refractor might serve you better.

I currently use a 12-inch dob but started with an 8-inch and don't regret it. When I first got the 8-inch I thought it was huge.

[pbyrne]

Having recently picked up a 12" Orion dob it's hard to imagine how big it is, the tube weights in at 50lbs and the base at 35lbs. Assembled it stands as tall as me, about 5'10" so it's not a single movement scope in terms of scope and base at the same time. With an instrument this size one thing to consider is where is it going to be stored? Moving a tube weighting 50lbs and about 5' in length up and down stairs will quickly become tiresome.

I agree with acey, if this is your first scope then go for the 8", get to know the sky and then in a year or two move on up.

Paul

[acey]

I used the 8-inch for 9 years and could have happily have gone longer as there were still so many things I hadn't seen with it, but figured if I was ever going to get into the heavy-duty league then I ought to do it before I was too old.

My 12-inch is a flextube which is collapsible and therefore pretty easy to move around, but the base still has to be moved separately (and it's huge - only just fits through the rear door of my car onto the back seat).

The 8-inch, tube and base together, was an easy one-hand lift.

If you're trying to make the most of a half-hour break in the clouds then smaller is definitely better.

Another good point raised by Paul is height. With the 8-inch I could sit on a camping stool and find the eyepiece always at a convenient height for viewing. Larger aperture means a longer scope and a bigger variation in eyepiece height: with the 12-inch I have to use an adjustable stool (some people use ironing stools; there are special astro chairs that are easier to adjust but cost lots).

With the 8-inch I saw all the Messiers and Caldwells above my horizon and hundreds of NGCs. For planetary views I find the 12-inch no better than the 8-inch, because the latter had less issues with internal reflections causing stray light and loss of contrast. I'll deal with that by flocking when (if) I can be bothered. Suffice to say I don't think of it as a dedicated planet scope (or of myself as a dedicated planet observer).

I look at faint galaxies from dark sites (Abells, Arps, Hicksons etc). The 12-inch is great for that, and worth the effort of getting it there. But if you want to see Saturn's rings or M51 there are easier ways that won't give you back-ache or a hernia.

[John]

I used the 8-inch for 9 years and could have happily have gone longer as there were still so many things I hadn't seen with it, but figured if I was ever going to get into the heavy-duty league then I ought to do it before I was too old.

This is exactly the stage that I am at as well. I sold my 8" F/6 Skywatcher dobsonian and got a 12" Meade Lightbridge dob. I don't regret doing this but I have not been able to use the larger scope as much as I did the 8" because the latter was practically a "grab and go" scope. At F/6 the 8" was easier to keep in collimation as well.

That said I think the 12" scope is the first I've had that really starts to show the brighter DSO's like they look in pictures - globular clusters in particular are stunning with a foot of aperture

John

[doat1]

I have used an 8in before and they are big and the 10 or 12" dob i posted will be probably as tall or taller than i am but i don't worry about that. I will store the scope downstairs covered and protected so lugging it up and down the stairs won't be a problem. Unfortunately i will be mostly using the scope in a neighborhood but on some nights i can see a lot of things, also my brother and i plan on driving further up north in an isolated area where there is not a single source of light for miles other than cars. Last friday i could see Mars and Venus with the naked eye but when i tried to look at them with my 4in Bushnell i could not get any detail just a bigger spot of light, however, it was still an amazing sight to just being able to see those planets.

I use this website to know what planets i can see and quickly find http://stardate.org/nightsky/weekly.php

[albedo0.39]

But if you want to see Saturn's rings or M51 there are easier ways that won't give you back-ache or a hernia.

Spot on.

I think that a 10" or 12" scope is going to cover most of the bases you'll ever want to see in the sky - and more. The only issue with the larger scopes has to be portability.

I've added wheels to mine based on good old fashioned copying someone elses idea. I've seen the Lightbridge 12" in the flesh and couldn't believe how much more compact it is than the 16". Still, they are not exactly "svelte" devices these big dobs and a good strong back or donkey might be essential if you plan on lugging it anywhere

What amazes me though is the video I've seen on a very slim lady assembling a 25" Obsesson scope in a matter of moments and I swear it looks a lot easier than my "Lardbridge"

[doat1]

Portability won't be a big issue i could do what many of you have done and add wheels but it's not that big of a problem for me.

[John]

Portability won't be a big issue i could do what many of you have done and add wheels but it's not that big of a problem for me.

In which case you might as well go for the 12" and then you won't always be wondering about "what might have been"

John

[doat1]

Thanks and thanks to everyone for your helpful input, you guys are the best. Does anyone know where i can buy a camera mount so i can take pics of my findings? I have a Canon EOS Digital rebel XTI.

[Talyn]

Hi,

From a dark site there are many fine nebulae you can see, too. When winter comes, Orion is wonderful - M42/43/ but forget the Horsehead. In the summer the Milky Way offers a host of targets. Do you have good star charts? Computers are not much use because they blind you!

Olly

The Horsehead is notoriously awkward. I have looked for it on several occasions with a variety of instruments and can only ever to have claimed to have seen it once - and even then it was only a 80% claim! Under average skies - as most of us have - with a 12 inch I doubt you'd see it.

Computers can be useful, but get several sheets of red acetate (in any art shop) to dim the screen sufficiently so it doesn't affect your vision.

A 12 inch scope will show you tons of stuff, as others have said. Forget the Messiers (too bright! ), a big portion of the RNGC is avaialbel with a 12, that'll keep you busy for years.

[doat1]

RNGC, Messiers? What are these?

[Doc]

They are catalogues of deep space objects. Charles Messier wrote the Messier catalogue and it consists of 110 objects that varies from galaxies to nebulas.

The NGC catalogue is along the same lines but has 7800 objects I think and these are not a bright or as easy to find as the main Messier catalogue.

You then have numerous other catalogues such as the IC.

Have a look here.

Cosmic Voyage-The Online Resource for Amateur Astronomers

[haitch]

Thanks and thanks to everyone for your helpful input, you guys are the best. Does anyone know where i can buy a camera mount so i can take pics of my findings? I have a Canon EOS Digital rebel XTI.

If you really want to get into imaging then maybe a dob isn't right for you. Even if you get one of the newer dobs with computerised goto you will get field rotation in longer exposures (because the sky does not rotate along the same axis as the scope) although planets should be ok I think. If you went for an expensive equatorial platform for it to sit on you could over come the field rotation.

There is still one major problem though using a camera on a dob...Balance. Hanging your DSLR of the top end of a dob is going to cause you tremendous problems trying to stop it nose diving towards the floor. Even balancing out with weights at the rear may not provide a great solution as the extra weight may also cause the tube/truss to flex and affect collimation.

In any case if imaging is what you want to do then aperture isn't so important - a camera can pick up far more through a smaller aperture on a long exposure than your eye can see.

The reason a Dob gives you so much aperture for your cash is because of the mount's simplicity. Once you start moving away from that simplicity you begin to defeat the object in terms of price and ease of setting up.

I'm not saying imaging and dobs can't go together but they're not an obvious pairing. IMO

[doat1]

Yea once i saw a dobsonian i thought it would be difficult to mount a camera on it for the same reason you said and the stress on the camera itself. Thanks.

[haitch]

Yea once i saw a dobsonian i thought it would be difficult to mount a camera on it for the same reason you said and the stress on the camera itself. Thanks.

I'm in the process of altering my tube & mount on my dob. Mainly due to balance issuess caused by simply upgrading the focusser to a 2". For the past couple of months I've had to hang a bag of rocks off the back end.

[Demo johnny]

Looking at dob's sw250 sw300 flextube or lightbridge12" couple of questions. Price for the sw250 £450 not bad but is the price jump for the sw300 and light bridge justifiable + £350 -£400. I know they are portable and that's in the price but take that out of the equation can you justify the extra?

[John]

Looking at dob's sw250 sw300 flextube or lightbridge12" couple of questions. Price for the sw250 £450 not bad but is the price jump for the sw300 and light bridge justifiable + £350 -£400. I know they are portable and that's in the price but take that out of the equation can you justify the extra?

The 12" will gather more light, resolve more and show deep sky objects, etc, etc than a 10". Whether that additional performance is worth the extra price to you is a personal decison I guess. The same question could apply to 6" or 8", 8" or 10" and so on. Some say a 2" difference in aperture is hard to notice and some say it's significant to them. If you are primarily interested in viewing faint deep sky objects then any aperture increase is worth having perhaps. Above 12" though the scopes seem to become a lot for one person to handle from a practical point of view.

If you can transport a scope to dark skies then it's performance will jump considerably on the fainter objects so, if that is the plan, getting something transportable rather than the ultimate in aperture, might be important.

[bingevader]

Looking at dob's sw250 sw300 flextube or lightbridge12" couple of questions. Price for the sw250 £450 not bad but is the price jump for the sw300 and light bridge justifiable + £350 -£400. I know they are portable and that's in the price but take that out of the equation can you justify the extra?

But it's also a lot more mirror!

Depending on the quality, you could pay an extra £200 just for the mirror itself.

Cheers

[Mike73]

If you can manage the size of a 12" and can afford it then I'd definately say go for the 12". Theres lots of sketches on my blog which should give you a pretty good idea what sort of views they give of objects.

[Demo johnny]

Nice sketches.

Guess where I am coming from is looking through a 10 then looking through a 12 side by side on the same night am I going to say yep worth an extra £400.

Or is it get the 10 and better eyepieces, uh filter and crayford spend the extra money on other stuff.

[John]

Nice sketches.

Guess where I am coming from is looking through a 10 then looking through a 12 side by side on the same night am I going to say yep worth an extra £400.

Or is it get the 10 and better eyepieces, uh filter and crayford spend the extra money on other stuff.

Better eyepieces and the other stuff won't give you more light. As to whether you feel the difference is worth £400 - how can anyone but you answer that ?.

[scarp15]

Both apertures will undoubtedly provide great performance, though I think that because you are already considering the two options, then the 12" flextube, for its extra light grasp might make the most sense. It is hefty but is a snug fit in a compact car so you can drive to darker locations. As for investing and upgrading in additional gear - that too is completely understandable, however take your time, gradually save up again and trawl the second hand markets - 'Rome wasn't built in a day' so to speak.