Another One Bites The Dust- Aperture Fever Won.

[Suzy]

:hi:Hi everyone,
Though I've had fantastic views and many an enjoyable night :love:with my 6" dob., the time has come for me to upgrade.:whistle: I am planning on upgrading to an 8 inch dob. :D(after much brainstorming on a 10", I've concluded that I won't be able to comfortably handle this by myself,:rolleyes: so I won't be going there).

The 8 inch collapsible dobs are on sale at the moment for only $550, compared to the solid tube at $500. May I please ask for your help with regards to the pros and cons of the collapsible dob (aside from the obvious 3kg lighter weight)? :help:

:question: Some questions that cross my mind are:

1) Does this need colminating everytime it's set up?

2) It seems strange to have the scope open to dust and elements. Even if you do cover with a shroud, can dust get in (I loathe dust on my scope).

3) Is dew more of a problem with these.

4) Is it fiddly to put together in the cold and dark.

5) Anything else I should be aware of.

I am leaning more towards a solid tube,:confuse3: however I want to make an informed decision before I go ahead and purchase, as this is the scope :astron:that I plan to keep for a very long time to come.

:thanks:Many thanks for taking the time to help me out . :)

Regards,
Suzy.

[Liz]

Hey Suzy :)

I have the 10" collapsible Dob, and I think its/shes great. Easier to manage and transport and lighter, as you said. i have no problems. Easy to collapse and set up again.
They keep their collimation very well, which is great as I am a hopeless collimater person. :lol:
I had friends make me shroud to help protect from light and dust. You need a shroud as light can get in when viewing, esp public nights, whooaa!! they are dear to buy so get one made if you go down that track
After use, you collapse it, so no dust can get in anyway. It comes with (well mine did) a good Dob cap for the first section of scope, and a flimsy cap for top, which keeps falling off. A good protection for dobs is to snuggle thm into a sleeping bag for protection after use, and store them horizontal.
No more dew problems than normal, which is horrendous up here!!!
I love the look of the black diamond finish on mine, but whatever you like you can get girl.
Good luck, and keep researching. :)

[astro744]

An 8" f6 is exactly the same focal length as a 6" f8, just a little larger in diameter. If you can handle the 6, then the 8 will be manageable and much easier to just 'plonk' outside and be observing in minutes (planets will of course require mirror cooling). If you go with the 10" then perhaps the truss or semi truss is better from a weight point of view. The truss 'scopes do take longer to set-up and yes collimation should be checked and is often needed. You will also need a shroud of course. Note too that shiny aluminium truss poles will affect contrast.

The 8" will give you 1.78x the light gathering power over a 6" wheareas a 10" will give 2.78x over a 6". A good upgrade path is 6" - 10" - 16" with each jump giving over 2.5x a brightness increase. Another good upgrade path is 8" - 12" - 18" with each brightness jump being 2.25x.

You will notice a difference between your 6" and 8" particularly on globulars as you will be able to resolve more and the stars within the globular will be brighter. Planets will appear similar but the resolution gain can be detected in good seeing. The brightness gain is important on planets mainly at the high power end where you will get a larger exit pupil at the higher powers.

If you are set on an 8" then I would go with an 8" tube for general use at home or a trip to a dark sky and would only consider an 8" truss if I was travelling. Otherwise consider a 10" truss or semi truss design.

Note you can get a hand trolley and strap the dob base and tube to it with luggage straps to make it easier to move around. Get one with large pneumatic tyres rather than solid tyres to take the bumps better. This would work well with an 8" or 10" tube telescope.

If you have aperture fever then going from a 6" to 8" may be like taking one paracetamol when you should have taken two; the fever may go away but could just as likely come back with a vengeance.;) Whatever you choose, enjoy!

Note on f ratio: Your 6" is f8 and an 8" will likely be f6. A 10" will likely be f5 and will show more noticeable coma and also require premium eyepieces to perform well. You may even need a Paracorr at f5 if coma bothers you.

[Paddy]

Hi Suzy,

I haven't had a lot of experience with collapsible dobs, except for a friend's Saxon collapsible 8" which seems to work very well. I use a truss dob which collects no more dust than my former solid tube 12". The secondary does tend to dew up and I use a dew heater which works fine. But I don't use a shroud. If you have a shroud, there shouldn't be any difference dew wise compared to a tube. Collimation is actually a little easier on my truss dob than it was with my tube scope.

Whichever you chose, you'll enjoy it immensely. But I wonder if it would be worth having a play with a 10" to see how hard/easy it would be to handle? 8" very good, 10" very very good (provided that it is easily usable)

[RobF]

+1 for what Astro said - there's likely to be a much better "wow factor" going to the 10" from a 6" over 8" if you look at the area numbers. If at all possible would suggest looking at ways to save space and weight (collapsible), money (IIS classifieds....) and ease of use (small trolley if need be - many threads along these lines here).

Resistance to the aperture fever is futile - you will be assimilated (err sorry - Star Trek taking over there....:rolleyes:)

[torana68]

I feel a great disturbance in the Force, as if millions of voices suddenly cried out in terror and were suddenly silenced. I fear something terrible has happened. Suzy has bought an 8".....

[that_guy]

hehehe... i upgraded from 8" to 10... you can see the difference immediately!! these guys have 'em cheap! also free shipping. http://www.theastroguy.com.au/telescopes_dobsonians.html

[leon]

Suzy, my goodness you have been captured, :eyepop: bugger, but i'm afraid you won't be able to get out of this one, :D but at this point I congratulate you, well done. :thumbsup:

I say this for this reason, one goes, one enters. ;)

Suzy, I have been doing Astronony forever, I just turned 60, on June 13th, and I have given it away, well my stuff, that is, I still like looking up so to speak. ;) ;)

Life changes, and I am going to do other stuff, I have plenty of nice L Glass to keep me happy.:D:D

One leaves, One enters, go for it girl. :thumbsup: :thumbsup:

Leon :thumbsup:

[floyd_2]

Suzy,
if you can manage it, I would recommend upgrading to a 10" rather than an 8". An 8" seems like too much of an incremental upgrade. Go for the maximum aperture that you can handle / afford. There may be ways that you can handle a 10" without having to lift it here and there, depending on where you observe from vs where you store your scope. For example, as Astro mentioned, you may be able to use a hand trolley to move a 10" scope around. Alternatively, perhaps a set of handles with wheels might do the trick so that you could wheel the fully assembled scope around sort of like a wheel barrow.

In the case of my 10" LX200GPS - I find it too heavy to move around / assemble etc, so I have it permanently mounted on a custom wheely bar sort of set up with leveling bolts - so I just wheel the fully assembled scope to my observing pad, level it, and I'm off and running with zero effort. If I had to carry that scope and mount it on the wedge every time I wanted to observe, I think I'd end up selling it for something more convenient.

I've used tube dobs and truss dobs and have liked them both. I had a 10" f/6 tube dob for years and absolutely loved it. I think that 10" is the sweet spot before you really start getting into heavy / less convenient scopes. I'm a firm believer that the more convenient a scope is to use, the more it will be used.

My 15" truss dob was a little more trouble to move around and quite heavy. However, the views more than made up for the inconvenience. I made a set of handles with wheels for the rocker box of the 15" but could never bring myself to drill the female threaded sockets into the cabinet :( So, those handles were never used even though it meant that I could have left the 15" fully assembled at all times and cut the fuss down to almost zero. I guess the point here is that there was a way of increasing the convenience of using that scope that would have been perfect (if I wasn't so scared of drilling holes in an obsession).

I'm sure you'll end up with just the right scope for your needs regardless Suzy. If you think a larger scope would be better, I'm absolutely sure that there'll be a way for you to increase the convenience / ease of moving it and setting it up.

Dean

[ZeroID]

Hi Suzy, I've been debating the 8" - 10" decision as well but I'm upgrading from only a 4.5". I am also building my own truss dob using only two poles ( according to current plans which may change ). From my point of view the build is only 50 mm bigger in the cell size but the same length as a 8" f6. It is also slightly dearer for the mirror but the deciding factor was the light grasp of the 10" over the 8". It goes from 841 to 1317, a significant factor. My 4.5" is 265 so I'm expecting to see a big change. Light grasp on a 6" is 472 btw.
I'm adding fan temperature control to the primary and heater to the secondary, we get the heavy dew here as well.
I'll investgate shrouding if it proves necessary but I have access to a good dark site.
Good luck with your choice but aperture rules as they say.

[rmcpb]

Suzy,

If you haven't committed to the 8" already really consider a collapsible 10" and a luggage trolley for movement. It will really grab you hard.

What's next, a 16"................................... .......

[astroron]

:hi:Suzy, I understand that you may be going to AstroFest?If so and you haven't ordered a scope yet why don't you put it off till then as you will be able to see lots of scopes and get a feel for what is available:)
Also you may Pick up a Bargain from the Vendors :D who are there for the last couple of days:thumbsup:
I to reckon that with a bit of thought in the way you move the scope in and out of storage can make the 10" a better proposition :)
PS the collapsible Dob seems a great idea.

[sejanus]

get something like a lightbridge and put it on wheels

my 16" LB was quicker to setup than my 8" dob - it literally rolled out of the garage and that was it.

The exception is if you need to put it in a car.

I reckon get a 12" LB

[marki]

There will not be a great enough difference between the 6" and 8" to make it worth the hassle IMO. Best follow Ron's advice and check out as many different options as possible. That way you can get a better feel for what overall performance you want and what you can physically lug around. If the dob breaks down you will only have to manage the mirror box which will be the heaviest component.

Mark

[Suzy]

Thank you all for your input towards helping me make the right decision. I’m so very grateful (though utterly confused at the same time!) I have in fact tried out a 10” dob- I loved the view. The notable difference was on the Jewel Box Cluster. In my 6” the gold star is very tiny and you can just make it out, on the 10” it’s bright and very much there-you can’t miss it. Never tried an 8”, so was happy to compromise and settle in the middle of these two scopes. Size wise- the 10” really didn’t look that big to me, I could easily handle the size, the weight is another story. Say we put the weight issue aside and utilize a trolley, there are other concerns that I regularly come across reading, and these issues add to my issues of weight/transportability. Will the following be big issues for me…..


1)Collimation. I hear the 10’s need this regularly, especially after every car trip?

2)Dew problems. More of a problem with a 10”?

3)Cooling down period takes longer?

4)This is a fast scope at F5. How will this impact on my current premium eyepieces (Vixen lvw 22m, Petax xw10mm)?

5)The planets get very picky when it comes to less than desirable seeing conditions through larger apertures, as large apertures can magnify poor conditions that smaller apertures don’t reveal (as they don’t show as much detail). I regularly come across this point. Do I have to carefully pick my nights when I view planets?.

6)Lastly, a valid point I’m about to raise. The only other two females on here that I know of that have got 10” dobs: JJJnettie sold hers, and Liz went for collapsible. This isn’t giving me much confidence.

7)There doesn’t seem to be much of a difference between and 8” and a 10”, than
There is from a 6” to an 8”. I have detailed the differences below:

6” Resolving Power: 0.74 Faintest Stellar Magnitude: 13.6
8” Resolving Power: 0.56 Faintest Stallar Magnitude: 14.2
10” Resolving Power: 0.56 Faintest Stellar Magnitude: 14.7

From what I see, I see a whole magnitude difference between the 6 and an 8 (that’s 2 and a half times brighter, right?), but not even a mag. Difference between the 8 and the 10. I don’t doubt the 10 will give a better view on top of the 8, but from what it looks like there is a bigger jump from the 6 to the 8, than there is from the 8 to the 10. What do you’ll think?

I’m trying to keep in the forefront of my thinking, the classic line “the best scope is the one you use the most”. If the 10” ends up being quite a bit of maintenance (regarding the above points), I have to ask myself, would I really use it as much as I do now, in comparison with my 6”(despite stunning views).

I understand and appreciate that you'll are trying to give me the best advice, and believe me,I am taking everything you'll say into heavy consideration.

Regards,
Suzy.

[Suzy]

Aaaaaahhhh Sheeeeez! I knew the force would try and get me on this thread too. Seems I can run but can't hide. :prey2:
:lol:

[torana68]

[QUOTE=Suzy;604835]

1)Collimation. I hear the 10’s need this regularly, especially after every car trip?
shouldnt be worse than anything else? the faster you go the harder it gets to get it right, F4 can be not a lot of fun, F8 easy :D

2)Dew problems. More of a problem with a 10”?
here EVERYTHING has a dew problem :)

3)Cooling down period takes longer?
bigger bit of glass takes longer yes but most 10's have a fan , if not get one

5). Do I have to carefully pick my nights when I view planets?.
I can only say when a 4.5" sees a planet as a blurry spot the 8" see's a planet so i would assume ,and its what I hear, a bigger scope is less effected than a smaller one as it gets more light to your eye

Maybe someone here has a 10 they could lend Suzy to try?
Buy what makes you happy! (no that does not mean new shoes instead)

my 2c worth...
Roger

[that_guy]

Will you be keeping your 6"?? I have a 10" and i had an 8". You can see the difference when looking at nebuli and clusters.. I don't find the weight much of a problem. just take time setting it up. Would there be other people who might be able to help you?? I'm not a fit person nor am i the strongest. (i have nerve damage in my hand) but i can still lift it fine...!

[astroron]

Hi Suzy see my input


1)Collimation. I hear the 10’s need this regularly, especially after every car trip?
Why is everyone afraid of collimation? after you have done it a few times it becomes second nature.

If you pack it in the vehicle well enough and the roads are not too rough, then there shouldn't be much of a problem.

2)Dew problems. More of a problem with a 10”?

The more glass there is the longer it takes to due up IMHO.

3)Cooling down period takes longer?

Set up a bit earlier, look at say Nebular/ galaxies until it as cooled enough to look at Planets

4)This is a fast scope at F5. How will this impact on my current premium eyepieces (Vixen lvw 22m, Petax xw10mm)?

Not to sure on that one?

5)The planets get very picky when it comes to less than desirable seeing conditions through larger apertures, as large apertures can magnify poor conditions that smaller apertures don’t reveal (as they don’t show as much detail). I regularly come across this point. Do I have to carefully pick my nights when I view planets?.

A small Fuzzy Planet is just as bad as a large Fuzzy Planet.
You take your nights as you find them.

6)Lastly, a valid point I’m about to raise. The only other two females on here that I know of that have got 10” dobs: JJJnettie sold hers, and Liz went for collapsible. This isn’t giving me much confidence.

There is a lady who is on iceinspace, but doesn't post who takes her 10" scope out as often as she can ( more than most males I know.
Liz and Jeanette can come in and give their reasons for doing what they did.

7)There doesn’t seem to be much of a difference between and 8” and a 10”, than
There is from a 6” to an 8”. I have detailed the differences below:

6” Resolving Power: 0.74 Faintest Stellar Magnitude: 13.6
8” Resolving Power: 0.56 Faintest Stallar Magnitude: 14.2
10” Resolving Power: 0.56 Faintest Stellar Magnitude: 14.7

From what I see, I see a whole magnitude difference between the 6 and an 8 (that’s 2 and a half times brighter, right?), but not even a mag. Difference between the 8 and the 10. I don’t doubt the 10 will give a better view on top of the 8, but from what it looks like there is a bigger jump from the 6 to the 8, than there is from the 8 to the 10. What do
you’ll think?

The 10" scope well out performs the 8" scope, an increase of nearly a magnitude is considerable.


I’m trying to keep in the forefront of my thinking, the classic line “the best scope is the one you use the most”. If the 10” ends up being quite a bit of maintenance (regarding the above points), I have to ask myself, would I really use it as much as I do now, in comparison with my 6”(despite stunning views).

That is only for you to decide.
there is a price to be paid for everything
cheers
Ron

I understand and appreciate that you'll are trying to give me the best advice, and believe me,I am taking everything you'll say into heavy consideration.

Regards,
Suzy.[/QUOTE]

[Suzy]

Hi Tony,
I will be selling my 6".
As mentioned I've got a 6" and looked thru a 10", and you've had an 8". Say with the Jewel Box Cluster for example, what notable difference do you make between the 8" and the 10" performance on the gold star with these scopes?
Thanks,
Suzy.

[astro744]

I think the 10" resolution should read 0.46.

Note the magnitude differences can also be expressed in differences in light grasp. Light grasp over human eye open to 7mm = area of primary mirror / area of pupil.

eg. for 150mm telescope light grasp = 150^2/7^2 = 459
eg. for 200mm telescope light grasp = 200^2/7^2 = 816
eg. for 250mm telescope light grasp = 250^2/7^2 = 1275
eg. for 300mm telescope light grasp = 300^2/7^2 = 1836
eg. for 400mm telescope light grasp = 400^2/7^2 = 3265

Like I said in my earlier post, you will notice a difference between the 6" and 8" but the difference will be more pronounced between a 6" and 10". Likewise for an 8", you would notice the jump to 10" but a better jump would be to 12".

See if you can look through a 6", 8" and 10" on the same night with your eyepieces at a star party and then make a decision. The 10" being f5 will benefit from a Paracorr if you find the coma objectionable; only you will know.

[Paddy]

Hi Suzy

Bigger mirror, less dew.

with a fan, your mirror will be cool in 30 min. less if with a very simple mod you direct air flow over front of mirror.

collimation will be easy - 5 min each time at most.

I know a 60 year old lady with a 10" tube dob. she has no problems moving it around in her Nissan Pulsar.

My Vixen LVW 17 was a delight in my 12" f5 dob. I don't know about the pentax, but I don't think you're likely to need a paracorr at f5. And you will probably find planets better in poor seeing with a big scope as you'll have better resolution and won't push the magnification so mucj to see things.

Again, if you choose an 8" you will be happy. But really i think the only issue in favour of small is manageability

[that_guy]

I havent tried it out with the jewel box yet, but you can see the difference immediately in the core of omega cen. Also Eta Carinae, you can see far more detail and more light... I would sell my 8" for a 10" again if i had to!

[norm]

Hi Suzy,

I'll add to your dilemma.;)

F5 and premium eyepieces - I think you'll be fine. I have an F4.7 with a pentax 10mm XW - no issues.
Visual parracorr to reduce coma - to be honest you are most likely to get away with not having to purchase one. If it was faster say mine or lower, probably recommended.

Collimation - I don't think the size makes all that much difference. In terms of complexity, with the right tools, you can collimate in less than 2 minutes.

Cooling down - I don't think its that bigger issue, certainly when the weather gets warmer/summer months, maybe just pull the scope out 30mins earlier. I have a 14.5" and to be honest, I don't fuss over it too much - 30-45mins and she's right.

Dew - as people have mentioned, dew is always an issue. Main area imho is with the eyepieces and viewfinder (telrad etc).

Truss dobs - u can set these up in the dark no problems. I can set mine up jcompletely unassembled with a red torch in 10-12 mins. Once you have done it a few times, it becomes 2nd nature.

Understandably you want bang for your buck and your concerns are valid, but don't stress over it too much, things will fall into place.

So the decision? Go with a collapsible 10" Skywatcher or Lightbridge.:)

Good Luck with the decision.

Norm

[torana68]

:fight:
this could go on for a while..... where's the other girls for some insight on dragging a 10 around?

[Liz]

\\

I was the first to reply roger. ;)

Think Suzy is being led down the aperture track with a grin on her face. :lol:
The 10" is a lot bigger than the 8", but as I said, the collapsible is lighter than the solid 10" dob. It is managable, and more so with your hubby on hand Suzy. I thought your mind was set on the 8", but if you are tempted by the 10", then check them out ans see how heavy they are. :help: You dont have to carry them far ... house to car/car to house. Most places you set up are near/next to car. As in another reply, I use a trolly once set up = easy. :)

[ZeroID]

Re the size/weight issue which seems to be the big bugbear here. Remember an 8" f6 is the same length as a 10" f5 ( give or take a few mm) and only 50 mm more (2") in diameter. So height to eyepiece etc is not a problem and especially if it's collapsible it takes up very little more room in a vehicle. And that 2" extra diameter is mostly empty space anyway !! It's just a bigger hole.. heheheh
This is my reason for opting to go 10" over the 8".

I'd suggest doing the Astrofest Test before deciding. Look at the options. Good luck.

[Suzy]

:lol: I like you're thought process Brent :lol: You are right, portability concerns are my issue. I know I can handle an 8, and I have tried a 10" and have no probs using it. To me, it's really not that big at all. Just the moving it around issue, but as others have said, I can use a trolley and i will be happy to do that. My concerns now mostly lay within the list of points I detailed- the maintenance issues. I'm after ease and portability basically. I don't want it to be a hassle to get my scope out and then not use it much. I worry about that. I use my 6" all the time (weather permitting) as it stands now.

[Steffen]

To me this reads like 0.6mag between 6" and 8", and 0.5mag between 8" and 10". i.e. a more or less linear progression.

What matters less once you get to 6" and larger is the resolution. Under *most* circumstances the difference in resolving power won't matter much - how many times do you get 0.5 arcsec or better seeing?

You will see more of the fainter details not because of better resolution but because the image will be brighter, and a full extra magnitude between 6" and 10" is nothing to sneeze at. More light gathering power can also mean the difference between colour and monochrome.

When I was young an astro veteran told me not to waste money by increasing aperture in increments. Double it or don't bother, he said. If you have a 6" and crave more aperture go for a 12". If you have an 8" go for a 16". I believe there is some truth to this, because frankly, I haven't seen all that much difference between 8" and 10" Dobs (of which you'll see plenty at observing nights and star parties) apart from a somewhat brighter sky background and ever so slightly longer spiral arms.

Comparing an 8" with a 16" - or Alex' 17.5" - is a different story altogether. The other night at Katoomba the Blue Planetary was obviously and unmistakably blue through the 17.5" but white in 8" and 10" scopes. To my old eyes anyway.

I believe all it comes down to is handling/portability and price. Get the biggest Dob you can handle, transport and afford. If price is the only hurdle then I'd suggest saving up a bit longer rather than going from a 6" to an 8".

Now, going big most of the time also means going fast. Faster optics show their aberrations far more readily than slower ones. This means, among other things, greater care has to be taken when figuring the mirror, mirror disfiguration during cool-down will be more apparent, collimation is more critical and hence will need to be done more often, eyepieces need to be selected more carefully (i.e. from closer to the top shelf).

This means increased cost (scope and eyepieces) and less convenience (longer cool-down). The need for collimation shouldn't hold you back. After spending all this money I'd feel bad about not taking 5 minutes after every car trip to bring the scope into top collimation and therefore top performance.

Just my 2 cents. :)

Cheers
Steffen.

[Suzy]

Thankyou Steffen for taking the time to write such an informative and helpful post. You have given me some really good information to think over. You have covered everything very well. :thumbsup:

Thanks also by the way for the mention of the Blue Planetary - it was on my list of targets to see and I sure would have been expecting to look for something blue. I will still search for it, but I think I'll find it easier now that I have a better idea on what to expect to see.

Thankyou everyone else for your input and help so far as well. I appreciate the time you are all taking to help me.

[charsiubau]

I can't handle my husband's 10 inch solid tube dob even with a trolley.

I actually went for a different but more expensive solution - a 9.25 inch Celestron on a cg5 equatorial mount which I can carry and assemble myself with no help from anybody. The optical tube, the mount/tripod and the counterweights come in at 10 kg each. The downside is that it takes more time to get up and running than a dob. The upside is it has tracking and goto. I bought it for these two reasons: the biggest aperture I could manage alone and the tracking. That said, our most used scope is actually our Televue 85 mm refractor because of its supreme portability.

My main advice to you is, whatever you decide, before you buy the telescope, make sure you see it in the flesh and lift it yourself. And take a tape measure - things don't look as big in the shop as they do in the car or at home.

Good luck

[charsiubau]

I think 8 inches (dob or SCT) is the perfect compromise between portability and reasonable aperture. You can travel with an 8 inch and still have lots of room for other things or people in the car. I know of at least two females in our club who have 8 inch dobs. The difference over a 6 inch will obviously not be as great as with a 10 inch but it will still be significant.

However I would look at the 10 inch truss dobs before deciding. The Meade 10 inch lightbridge in particular looks quite small (compared to the GSO solid tube 10 inch) on the shop floor. On the Meade website it says the primary mirror housing is 30 lb, the mount 27 lb, the secondary housing 6 lb and the trusses 2 lb. You may be able to manage the weight of these components, but it will take longer to set up than a solid tube dob.

[Suzy]

Thankyou, Liz & Charsiubau, It's great to get a females point of view - you'll have been very helpful. :thumbsup:

[The3rdKind]

Gidday Suzy Q,

Long time since I communicated wif ya :D.
I've got the local park here now with keyed access along the driveway and keys to the toot as well. Some of us are going up on Sunday night (20th June) for a gawk festival. Get your eyballs over this side of town and have a gander thru mine again if you like.

One of the guys here has got a 12" Skywatcher collapsible (spellcheck) DOB and your not getting much more (eg Sombrero is very faint but visible from this location). The difference is he can pack it into his liddle rice burner with room left over and also the manouverability of the set-up is just beautifull. It is featherlight.

I'm out there very night with my 10" but am now wishin' hopin' cryin' prayin' to get my hands on some Meade S4000 super or Ultra wide angles. I say this because my 10" is ab fab but trying to manouver it on the mount is jerky and its easy to apply certain pressure and overshoot the object (especially high power barlowed down). If it was smoother and less clunky it would be a joy to use. Hence I'm going for the wider FOV.

BUT, I have ordered a ball bearing mettalic (spellcheck) ring which sits on the base of the mount to smooth this a great deal but I still have the Alt Az to deal with.

In your case, I'd give 12" very serious consideration as the collapsible dobs have superb movement at the mount.

Hope this helps Suzy, Hope you and yours are well, and hope to see you at our new site.

[M54]

Hi Suzy,

I know a woman who has a 10" solid tube dob and she says that she can lift it in and out of her car boot ok.
I think she collimates it each time it is used, at least after a ride in the car.
She uses it on a regular basis at the local astro clubs dark sky site.

I have a 5inch dob and plan to keep using it for quite some time yet, but when I do finally upgrade I'll be going through what you're going through now. And I'm terrible at making decisions!:P

So this thread is providing me with much interesting reading which I'll be filing away for the future.

Good luck with your decision.:)

[Starkler]

I recommend buying a 12" flextube and be done with it, as you're eventually going to end up there anyway ;)
Once that no longer satisfies you can talk about aperture fever :lol:

[Suzy]

Not so long ago I read an article from a very wise man.... he explained how appeture fever starts. :whistle: Every time he upsized, he could see a new feint fuzzy and just had to, had to, see it, so he would get bigger apperture, and then he would spot something new that was feint with this new and bigger apperture, and then the process gets repeated over and over again.

Knowing this evil :wink2: & self destructive journey now, I can quite happily look at a feint object and say "I don't really give a rats",:P I will just simply imagine/pretend/exagerrate :evil: about what it is.:lol: 10" is as high as I will ever want to go with this in mind.
See.. there is a cure for aperture fever after all - it's called "just don't go there" pill! :D :lol:

That all being said Geoff, I will race anyone to the front of the line to have a look :eyepop:thru your scope. Though then the fever will start up and I will have to search for this post to get my sanity back. Hey, I never said there was a complete cure!:lol:

[Starkler]

Yes theres that and it all comes down to how big an effort in time, money and effort you want to put into this past time and its always subjective and personal.

I started with an 8, upgraded to a 10, bought a couple of smaller scopes and then got the 15. A 6,8,10, or 12inch can be moved around and transported in a car by one person. My 15 wont fit in a sedan and has to go in a trailer. I think I could quite happily downgrade to a 12 and sell everything else just to save the transportation hassle. I really think a 12 hits a sweet spot of being the maximum easily transportable size and the minimum size worth looking through for dso's. After using a 15, a 10" wouldnt satisfy me but a 12 might.

Aperture always wins but only if its not too big and cumbersome to move and use. If you could move the scope from its storage place to its viewing place with a trolley without negotiating stairs etc I recommend the 12.

If you have to carry it around up stairs and around obstacles then an 8 might be tops.




If you were at the last Snake Valley camp you would noticed my scope looking very lonely and unloved due to Tims 22" being nearby. What amazing views! I need a bigger scope now:lol:

[mic_m]

Hi Suzy,

There is a misunderstanding on this thread about the weight of the collapsible SW dobs vs the solid tube versions; more specifically people have attributed the weights inversely. It is actually the solid tube SW that weighs less than the collapsible SW. The tube weight of the 8” collapsible (http://www.skywatchertelescope.net/swtinc/product.php?id=138&class1=1&class2=106) is 11kg and the tube weight of the 8” solid tube (http://www.skywatchertelescope.net/swtinc/product.php?id=51&class1=1&class2=106) is 7.98kg. The 10” the collapsible (http://www.skywatchertelescope.net/swtinc/product.php?id=139&class1=1&class2=106) weights 15kg while the 10” solid tube (http://www.skywatchertelescope.net/swtinc/product.php?id=52&class1=1&class2=106) weighs 12.42kg. It is worth noting that the optical tube of the 8 and 10” solid tube dobs are both about 1200mm long, which is the same as the collapsible dobs tube length when it is extended, however, the tube length of the 8”and 10” collapsible dobs can both be reduced to about 800mm. The bases are the same weight and the same dimensions for the solid tube and collapsible dobs in each size range, so that is not a factor of differentiation between collapsible or solid tube scopes but rather between 8”and 10” aperture.

The above tells you two things; if weight is the issue, not bulk, then the solid tube SW dobs are preferable. However, if it is bulk (more specifically OTA length) rather than weight that is your concern the collapsible SW dobs may be a better option given that the size of their optical tube can be reduced for transport or storage. However, given the difference in height is marginal when collapsed for the 8”-10” versions I don’t think there is any great advantage in going with a collapsible dobsonian. While the collapsible is not really any more complex or more difficult to set up there is the issue of obtaining an effective light shroud. This can be expensive and difficult to fit for the three strut design as the collapsable dob is not a true truss telescope where the truss structure supports the shroud and keeps it away from the light path.

Also, you should note that the original white tube versions of the collapsible dobs have their UTA knobs (the handle above the lower strut and below the focuser on the side of the UTA facing the LTA) in a slightly different location to the black tube versions. More specifically the black tube version have the knob moved down towards the lower strut away from the focuser. The holes cut in the Astrozap shroud for these knobs are cut for the black tube versions, not the white tube versions. So if you end up getting the collapsible version of the telescope and are planning to buy a shroud from Astrozap be sure to get one with a black tube.

As has been noted, while all other things being equal a larger scope will show you more, you have to consider the ease of use, if a telescope is too bulky or too heavy for you to easily move than there is really no point in buying it. If you can manage a 10” go with that, but if a 10” is too much of a hassle to move easily go with the 8” (8” is a decent sized scope and it will show an improvement over your 6”). But only you can determine what you are comfortable with using and transporting.

Good luck with your decision,

Michael.

[Liz]

Well, blow me down ... thank you Michael ... think I just presumed it was the other way round. :thumbsup:

[Suzy]

Woah! ....and blow me down too :scared2: (stand back Liz), Michael! Thanks so very much for that very informative post.

Yes, at the end of the day it has to come down to being able to lug it around for the person using it, at the risk of losing aperture. I realised putting it on a trolley will be no benefit to me as I would still have to lift it up on the trolley. The scope wouldn't get transported that often, so lifting it into the car wouldn't be an issue, as I will easily get help with that.

I have been planning strategies :confuse3: to adapt the 10" with really good wheels mounted onto a square base. I spoke with Ron from Sirius Optics and he said this is the norm. This has now inspired a bit more confidence within me to go for the 10". I want to be able to drag it around by the tension handles. I have a 6" dob on wheels that does this now, though the 10" will be a bit more complex.

Any help and ideas on this will be very welcome, though Ron from Sirius Optics tells me pneumatic wheels mounted on a square base is the way to go, these wheels will be very expensive... I wonder what the alternatives are...:question: Anyone else done the same thing?

So looks like I'm going for the 10" solid tube everyone! :thumbsup:

When I posted this thread, it was certainly not the track I had planned on heading. I knew the 8" would only be a marginal improvement (but improvement nevertheless. But you were all against it, (was so unanimous wasn't it?!) and I'm glad you'll made me question my decision and made myself look harder into how I could handle this bigger scope.

Thankyou all! :)

[mic_m]

Liz, you’re welcome for the information.

Suzy, I am glad that you found my post useful and congratulations on your decision!

This (http://www.jimsmobile.com/images/tpw_sw12.jpg) is probably similar to what Ron is talking about, its form JMI (http://www.jimsmobile.com/buy_wheeley_bars.htm).

This picture (http://stargazerslounge.com/attachments/equipment-discussion/24807d1247931127-skywatcher-skyliner-250px-black-diamond-auto-250px-blackdiamond-1.jpg) shows another possibility; it is a modified 10” Sky-Watcher where the owner has attached wheels (http://www.bearingboys.co.uk/CDTWBHB75GRT_Twin_wheel_castor-1040-p-17217-e) directly to the ground board. You can read about the attachment of the wheels in this thread (http://stargazerslounge.com/equipment-discussion/83583-skywatcher-skyliner-250px-black-diamond-auto.html).

Michael.

[Suzy]

Thank you again Michael, gosh you've gone to some trouble for me, I appreciate it. Well.. looking at the pics and the wheels, looks very similar to the mods I've got now on my 6". The wheels will need to be substantially larger to hold the weight and drag properly for a 10". I don't see those wheels performing so well with the pics you supplied. And I would probably need 4, hence a square platform.
But thank you, I do appreciate your input and certainly welcome it.

[marki]

I am not quite sure how a truss dob pulled apart into it's seperate components would weigh more then a solid tube dob which cannot be broken down easily. As a whole unit yes but not as individual parts.

Mark

[Suzy]

Hi Mark,
I was surprised when I saw the specs. on Ozscopes site of both the Saxon 10" & 10" collapsible, the tubes both weighed 12.42Kg. Saxon range anyway. I was a bit unsure of the truss's to begin with, but if they were much lighter I would have given them more consideration. I'm not worried about the size, more the weight issue to lug around. I don't think I'd have the patience to set it up everytime. After consideration of the truss's on the pros and cons, I've decided to stick with a sold tube anyway.

[Paddy]

Hi Suzy,

Sounds like a tube is the go if weight is more a concern than space and makes most things simpler. I did just want to point out that the collapsible dobs are easier to set up than ordinary truss dobs like mine or a lightbridge. My friend's saxon is just a matter of pulling the OTA to full extent and then tighten some knobs. very simple. But, again, a tube sounds the go.

[marki]

Fair enough. I understand your choice if you are not confident in breaking down and re-assembling a truss dob the solid tube would certainly be a better choice. Collimation is easy to do once you have done it a few times and know what you are looking for. I always check collimation before viewing as it makes a big difference and can be corrected in a minute or two. My initial question was how could a mirror box (the heaviest component of a truss dob) weigh more then an entire solid tube. Good to see you went for the larger aperture as well, you will keep the scope for a little longer before the next upgrade (in about 6 months ;):lol::D).

Mark