Is it worth upgrading?

[Manok101]

I've been fiddling with the idea of upgrading my 10" to something between a 14-20 truss and wondered if it was worth the purchase a bigger scope? If I do I'll likely sell or give away the 10" because more than two seems like too many scopes. Which of the bigger scopes should I look at? Is there anything other than price and move ability that I should look a when getting a bigger dob?

[Naemeth]

Portability is always an issue with big scopes. At 20", you'd definitely want permanent housing for the scope (an observatory preferably). Quite a few on here have a 16", and it seems to be much more common than an 18" or 20".

[SamAndrew]

Go as big as you can use, more apature is always a good thing, even a step up to 14"

If you're going to 16" or more I would keep the 10" initially as you may find you still use it when it's not worth setting up the big scope

[brantuk]

Up to 16" then a SW Flextube or a Lightbridge truss dob would be a very workable (asuming you're fit enough to move them round). If you go over that towards 20" then you should look at David Lukehurst dobs which have a great reputation for quality. Also for portability in the larger sizes look at Sumerian Dobs - they fold down to a suitcase size and again have great optics.

[swamp thing]

1340743076[/url'>' post='1557642']

Portability is always an issue with big scopes. At 20", you'd definitely want permanent housing for the scope (an observatory preferably). Quite a few on here have a 16", and it seems to be much more common than an 18" or 20".

I disagree with any truss Dob wanting to be in an obsy. The whole point of truss tube Dobs is to make them portable.

The very reason people started making them was to transport giant apertures to dark skies.

I would keep the 10" ( I have) then get the biggest aperture you can afford/ manage. I'm building a 20" at the moment.There is no way that is sitting in an obsy it's going to travel with me all over the place. Designed properly large aperture scopes are easier to get into the field than a mid sized SCT

To buy look at these

http://www.obsessiontelescopes.com/

Or

http://www.webstertelescopes.com/

These are both excellent scopes and easily portable

[Naemeth]

I disagree with any truss Dob wanting to be in an obsy. The whole point of truss tube Dobs is to make them portable.

The very reason people started making them was to transport giant apertures to dark skies.

I would keep the 10" ( I have) then get the biggest aperture you can afford/ manage. I'm building a 20" at the moment.There is no way that is sitting in an obsy it's going to travel with me all over the place. Designed properly large aperture scopes are easier to get into the field than a mid sized SCT

To buy look at these

http://www.obsessiontelescopes.com/

Or

http://www.webstertelescopes.com/

These are both excellent scopes and easily portable

It just does seem like it would be too heavy to be transportable. I wasn't however aware that they come with wheels (rather foolishly I must admit), you still wouldn't want to lift them much.

[DirkSteele]

Other thing to remember about the Godzilla dobs (16" up type stuff) is even with very fast mirrors (sub f4.5) you will find yourself needing a step ladder when pointing at the zenith, which in the dark, and possibly on your own, not all astronomers are comfortable with.

If you are prepared to deal with the hassle of importing from abroad, Obsession Telescopes are among the best dobs money can buy. David Kriege literally wrote the book* on building large aperture dobs and he is really nice and always happy to answer questions. He has launched his ultra compact range with F4.2 mirrors (you will need a paracorr) but they are the waifs of the large dob world making them very transportable.

*This book

http://www.amazon.co.uk/The-Dobsonian-Telescope-Practical-Telescopes/dp/0943396557/ref=sr_1_1?ie=UTF8&qid=1340746101&sr=8-1

[swamp thing]

The OP is in the states that's why I recommended Obsession or Webster scopes.

[Manok101]

With a 16" what can I see that I can't in a 10" and what's the highest magnitude object I can expect to see clearly? I think that's the absolute limit of portability for me.

[DirkSteele]

The OP is in the states that's why I recommended Obsession or Webster scopes.

So he is....Missed that. All the better for him!

[swamp thing]

I've had both a 10" and a 16" set up right alongside one another many times (I used to have both). The 16" is way out in front on everything.. The better the site the further the bigger scope seems to pull away. Galaxies that were just faint fuzzies in the 10" start to show some detail in the 16" some of the brighter ones quite alarmingly so. Diffuse nebulae grow considerably in size, structure and detail. Objects like the veil through a 16" with an O-III filter are photographic in detail. It's like a length of flaming rope accross the eyepiece. Simply stunning. The extra aperture really drags light through the most aggressive filters really well. I find the more aggressive the filter the better it works with big scopes. You'll definitely wamt an O-III with this aperture, couple that with a nice dark sky and you are really on to a winner. The Messier globs are all resolved pretty much to their cores. Stepping my 16" down gave me some of the finest planetary views I've ever seen and on the few still nights where full aperture can be used, the views are mindblowingly.

Planetary nebulae can be observed at very high powers and much more detail is apparent over a 10" The brighter ones like M57 threaten your night vision .

Only open clusters can be a problem as many are simply to big to fit into the FOV of a large scope. The ones that do are Wow! Though.

The jump from 10" to 16" is a good one and not something you'll regret.

Observing with a 16" scope is a whole new ball game IMO over the smaller scope. Pretty much anything you see in your sky atlas is visible, if your sky s a good one.

If you can afford it try and go for a premium one, you'll not regret it. I've used both budget and premium big scopes and the good ones are a pleasure to use, the budget ones need work to really get them up to speed. If you buy a budget one be prepared to do some work on it.

Youll want some fine eyepieces too. The views through premium glass coupled with big optics is very nice to say the least.

[umadog]

Other thing to remember about the Godzilla dobs (16" up type stuff) is even with very fast mirrors (sub f4.5) you will find yourself needing a step ladder when pointing at the zenith,

I think the cut off is a little higher than 16". Here's a 20" f/3: http://www.starmastertelescopes.com/MX20MO.htm My 18" f/4 doesn't need any sort of step stool either if you're 5" 9' and taller. Even the, slightly shorter people can get by with just a high observing chair. Yet larger scopes exist that only need a 2-step stool rather than a ladder. For instance, here's a 28" that doesn't need a ladder: http://www.astromart.com/articles/article.asp?article_id=829 In fact, if you're 6 foot tall you'll need no aid at all to view at the zenith. Of course those huge ultra fast (sub f/4 and sub f/3) mirrors cost a small fortune.

If the OP is in the states he should also check out Teeter, Starmaster, and Starstructure. It appears Webster may have an 18" in stock right now (if their site is up to date, that is).

Manok, you're asking what the magnitude limit of a 16" is. That you can easily look up on Google. It doesn't tell you so much, though. You need to know what the eyepiece views are like. A larger scope is going to be a major investment in both money and effort. I think you should go to a star party and look through one first. You need to see how big it is and see whether the improvement in the views is worth the cost for you. I really wouldn't sell the 10", though. Sell the 4.5". The 10" is the scope you'll want to pull out for quick looks. The difference between a 10" and a 16" is going to be bigger in dark skies than in light polluted skies. In light polluted skies a 16" is going to show more than, say, an 8" but the difference is less than you might expect. Go to dark skies and 16" is really going to pull ahead.

You say a 16" is the largest scope you can handle. It's no so simple, though. The question is which 16" are you talking about? A 16" Lightbridge is going to be bulkier and harder to haul about than an 18" Obsession. Remarkably, there are 18" scopes out there which weigh as much as a mass-produced 12". So you need to look into it carefully and run some numbers and take some measurements (door widths, for example).

[LukeSkywatcher]

I think the cut off is a little higher than 16". Here's a 20" f/3: http://www.starmaste....com/MX20MO.htm My 18" f/4 doesn't need any sort of step stool either if you're 5" 9' and taller. Even the, slightly shorter people can get by with just a high observing chair. Yet larger scopes exist that only need a 2-step stool rather than a ladder. For instance, here's a 28" that doesn't need a ladder: http://www.astromart...?article_id=829 In fact, if you're 6 foot tall you'll need no aid at all to view at the zenith. Of course those huge ultra fast (sub f/4 and sub f/3) mirrors cost a small fortune.

If the OP is in the states he should also check out Teeter, Starmaster, and Starstructure. It appears Webster may have an 18" in stock right now (if their site is up to date, that is).

Manok, you're asking what the magnitude limit of a 16" is. That you can easily look up on Google. It doesn't tell you so much, though. You need to know what the eyepiece views are like. A larger scope is going to be a major investment in both money and effort. I think you should go to a star party and look through one first. You need to see how big it is and see whether the improvement in the views is worth the cost for you. I really wouldn't sell the 10", though. Sell the 4.5". The 10" is the scope you'll want to pull out for quick looks. The difference between a 10" and a 16" is going to be bigger in dark skies than in light polluted skies. In light polluted skies a 16" is going to show more than, say, an 8" but the difference is less than you might expect. Go to dark skies and 16" is really going to pull ahead.

You say a 16" is the largest scope you can handle. It's no so simple, though. The question is which 16" are you talking about? A 16" Lightbridge is going to be bulkier and harder to haul about than an 18" Obsession. Remarkably, there are 18" scopes out there which weigh as much as a mass-produced 12". So you need to look into it carefully and run some numbers and take some measurements (door widths, for example).

WOW. I have to say that for a 20" and a 28" scope, both of those in your links look amazingly portable and usable. I for one thought a stepladder would be needed for such big beasts especiaslly a 28".

[Mike73]

The 28" has a 7" secondary!!! :eek:

[LukeSkywatcher]

The 28" has a 7" secondary!!! :eek:

WOW..................Thats almost as big as my primary on the 8SE.

[umadog]

WOW..................Thats almost as big as my primary on the 8SE.

And it's still only a 25% obstruction. But, yes, when you crunch the numbers it's astonishing how how low-profile a very large aperture can be. Their problem, of course, is that they're still very heavy (weight is all in the mirror) and very wide. So it doesn't matter how short they are, they'll still need a trailer.

Here's another: plenty of us will have seen a 12" and told beginners that it's rather bulky for a first scope. The standard ones are bulky, but check out this 13" "Zip Dob": http://www.bbastrodesigns.com/ZipDob/ZipDob.html The bright, wide-field, images it produces sound stunning. It's easy to relate to how portable and small it really is, since most of us will have seen a 12" Dob at some point.