8" GOTO Dobsonian - Collapsible vs Solid tube

GeeM (Graeme) · #1 10-01-2015, 06:03 PM

Hello everyone, this is my first post. I'm a newbie to astronomy and my head hurts with the variety of choices on offer for my first telescope.

An 8" Dobsonian seems to come highly recommended as a good beginner platform so I have been researching the options. I really like the idea of a goto mount so that I don't have to keep nudging the scope to keep the image centred.

I am comparing features between the Orion SkyQuest XT8G and the Sky-Watcher Black Diamond collapsible GOTO 8-inch Dobsonian.

I am a little concerned about the collapsible design of the SW. It looks like there is more opportunity for collimation to be an issue. Should I be concerned about getting a collapsible vs solid tube?
Are there any significant differences between the goto systems I should now about?

Cheers
Graeme

creeksky (Pete) · #2 11-01-2015, 12:33 PM

Hi Graeme,welcome to Iceinspace.
I am new too, so cannot help a lot ( others with expertise will know) I have just acquired an 8" solid tube Dob,yet to use in the paddock for the first time-cloudy

I think a GOTO will only take you to an object not track it,( I could be wrong) EDIT: they do track.
Many say you will not learn the sky, as it's easier to just let the GOTO do it.
I have no idea yet where DSOs are and whether they stay relatively there each night in the same areas of space-moving as the Earth does.
I can pick out some constellations easily,very few.
It would be nice though, to look up at a star and not have to refer to a chart,or an app on my tablet or phone.Then be confident of it's name.
I can pick out Sirius,know Jupiter when it is up,guess Mars usually and sometimes Saturn,by naked eye.
I can say your head hurt will ease a great deal once you have a scope-good luck!

raymo · #3 11-01-2015, 01:03 PM

You can rest assured that the collapsibility of the SW scopes causes no problems with collimation. The collapsible section of the scope is built like a brick outhouse. My 10" actually requires less frequent collimation than
my equatorially mounted 8" solid tube one.
I've never seen anyone post concerns about their experience with them,
and they are popular, so there are many of them out there.
Pete, all Go To scopes track whatever object you go to.

GeeM (Graeme) · #4 11-01-2015, 01:13 PM

Thanks Raymo,
That's good to know. Is it necessary to cover up the gap with a cover to keep stray light out?

Good luck with your new scope Creeksky! It sounds like your are very fortunate to have a truly dark sky location.

raymo · #5 11-01-2015, 01:40 PM

Pete and Graeme, if you are truly interested in getting enjoyment out
of your scopes, and maybe passing on your enthusiasm to others, you will
learn the sky bit by bit[there's no hurry, unless you are old like me] and
over time you will see your favourite objects come and go with the seasons, and almost look upon them as old friends.
GoTo scopes are an enormous help to novices for finding objects, but do
encourage laziness. It has been my experience that a sizeable
percentage of people that start with a GoTo scope never go on to learn
much of the sky, except maybe a few of the most well known objects.

Graeme, the primary mirror is deep down inside the scope, and I have
never found a great need for a light shroud. My wife made me one, and
other than trying it out, I've never used it. Maybe it would be useful if I
were surrounded by a host of streetlights.
raymo

Allan_L (Allan) · #6 11-01-2015, 01:58 PM

I agree with everything Raymo has said, and highly recommend a Skywatcher collapsible DOB.
The shroud can also help keep dew out of the system(IMHO)

barx1963 (Malcolm) · #7 11-01-2015, 05:49 PM

Just a further comment on Go To scopes. I have only limited use of one and found the experience frustrating. Using a non Go To was much quicker and easier - once you know your way around the basics of the sky, which is not difficult. A simple planisphere or all sky chart will enabl you to locate the main constellations and bright stars and then use them to star hop, very easy and satisfying once you get the knack. And it only takes a few sessions to become quite quick at it.
Also don't forget that you still need to be able to align a GO TO, if you cannot distinguish Archernar from Canopus or Belelguese from Rigel (or Rogel from Rigel Kentaurus, that's one that often throws beginners!) a Go To scope will be hard to use.

Malcolm

GeeM (Graeme) · #8 11-01-2015, 06:14 PM

Thanks for the advice guys. Buying a scope is incredibly difficult when I don't have access to others with one to try out. At least 1000km to the nearest one

creeksky (Pete) · #9 11-01-2015, 06:26 PM

Quote:

Originally Posted by GeeM

Thanks for the advice guys. Buying a scope is incredibly difficult when I don't have access to others with one to try out. At least 1000km to the nearest one

You never know, just put out to the universe that you need one, and the distance/wait will be shortened.I gave up and settled for a skywatcher 130p (budget constraints).
Within 12 hours one appeared bigger and better for exactly the price I specified.

raymo · #10 11-01-2015, 07:14 PM

Yet another comment on Go To scopes. Not all Go To scopes require you to know any stars. The Celestron SLT series allows you to use any bright
stars you want. Maybe some other brands do, I wouldn't know.
raymo

creeksky (Pete) · #11 11-01-2015, 07:41 PM

Quote:

Originally Posted by GeeM

Thanks for the advice guys. Buying a scope is incredibly difficult when I don't have access to others with one to try out. At least 1000km to the nearest one

Looks like you have already decided on an 8 inch GOTO

Maybe without the GO TO capacity you could get a 10"? Or More?
Bang for buck, I have been told.
I'm now concerned if I go to a star party, look through a 10"or 12"or more I am going to go back to my 8" and put the dust caps back on and sulk.

So maybe get the best you can without "automatic goto" The stars are not going anywhere, but your money will.

raymo · #12 11-01-2015, 08:36 PM

Pete, I would try your damnedest to avoid the dreaded aperture fever,
and let logic and reason guide your purchase. No matter what size scope
you get, there is always the chance that you will get to look through a bigger/better one, and be envious of it's owner.
Rule no.1 The best scope is the one that gets used. I used to teach a
basic adult astronomy course, and several of my keener students bought
scopes ranging from 12" to 16". One year later all had been sold.
Large/heavy scopes demand commitment. You can pop outside easily
any time with an 8" and, if you are reasonably strong, a 10" also.
12" to 16" can start to become a chore, and anything larger than that,
depending on it's type of construction, can become a labour of Hercules.
In short [a bit late for that], an 8" is a great compromise scope which should keep you happy until or if you decide to go larger.
Sorry about the verbal diarrhoea.
raymo

GeeM (Graeme) · #13 11-01-2015, 08:51 PM

It's because of voices of reason like yours Raymo that I settled on the 8" aperture. It seems to get a lot of recommendations as an ideal scope to learn on. It sounds like problems with atmospheric turbulence become pronounced with larger apertures and might steepen the learning curve.

My reasons for being interested in goto are not really for just being taken on a tour of the night sky. I am reasonably comfortable with the southern skies major features (naked eye visible) as I have been touring the skies with binoculars for a while now. I am more interested in the tracking ability of go to to lock on to a subject so that I don't have to keep bumping it all the time. I'd like to have a crack at basic moon photography also. So it seems like a good fit for me & I can push it around manually too.

raymo · #14 11-01-2015, 09:00 PM

Great choice, and I don't know about the Orion scope, but with the
SW collapsible all you need to be able to try some lunar imaging
is a T-ring to attach your DSLR to the focuser. Most lunar work is
done with a webcam or similar, but DSLRs can produce good results.
raymo

creeksky (Pete) · #15 11-01-2015, 09:06 PM

Quote:

Originally Posted by raymo

Pete, I would try your damnedest to avoid the dreaded aperture fever,
and let logic and reason guide your purchase. No matter what size scope
you get, there is always the chance that you will get to look through a bigger/better one, and be envious of it's owner.
Rule no.1 The best scope is the one that gets used. I used to teach a
basic adult astronomy course, and several of my keener students bought
scopes ranging from 12" to 16". One year later all had been sold.
Large/heavy scopes demand commitment. You can pop outside easily
any time with an 8" and, if you are reasonably strong, a 10" also.
12" to 16" can start to become a chore, and anything larger than that,
depending on it's type of construction, can become a labour of Hercules.
In short [a bit late for that], an 8" is a great compromise scope which should keep you happy until or if you decide to go larger.
Sorry about the verbal diarrhoea.
raymo

Thank you raymo,
I'm sure I will be blown away by just seeing faint smudges, I can always look at the planets,also.
Or even the moon, I have been tasked by an elderly neighbour to find her acre she bought from "the big cheese"? I know I will not get that close but within the vicinity.
It's all fun to me, I woke up like a kid with a Christmas scope like many years ago, This will have to be a bit better, surely?Than a 20 mm -40mm early 1970's refractor?
Though my folks went to the best sellers back then, in Chatswood Sydney.
That gave me heaps of fun, climbing up a ladder onto the carport roof and setting up, tracking Jupiter and Saturn, the moon and a few pin dot stars.
I need this hobby, already without yet observing it has been a journey giving me hope,
A life saving hope. And a thrill, so to see the stars better will be a joy...
And I hope to compare notes if Graeme gets a GOTO- I will have to find things manually (or cheat with my SkyEye app)

Sorry Barx1963 I will try charts too- its all good!

GeeM (Graeme) · #16 11-01-2015, 10:42 PM

We'll definitely compare notes Pete! Looking forward to it.

Well my mind has been put at ease, I am happy to order the SW collapsible now. Thanks for the advise and support gents, much appreciated.

Cheers,
Graeme

Allan_L (Allan) · #17 11-01-2015, 10:59 PM

Further on Skywatcher GoTo Dobs,
You don't have to align them.
Just plonk it down and use it as a manual push to.
or power it and you can "nudge" it with direction buttons
or, just level it and point it north before turning on and (it will not goto, but) it will track. (according to the manual)

creeksky (Pete) · #18 11-01-2015, 11:17 PM

Quote:

Originally Posted by GeeM

We'll definitely compare notes Pete! Looking forward to it.

Well my mind has been put at ease, I am happy to order the SW collapsible now. Thanks for the advise and support gents, much appreciated.

Cheers,
Graeme

Good one! Let us know when it arrives, keen to know how it pushes a Dob around to align it? must have some kickass power?
No power here unless I run a lead across the road to my "observation site"
Your head ache is almost over-clear skies!

GeeM (Graeme) · #19 12-01-2015, 03:14 AM

Sounds good Alan. I've just got home from my dark site after taking some photos of the Lovejoy comet. Had a ball out there tonight with my binoculars. I'm really excited to see how much brighter the image is going to be with the 8" dob compared to 10x50 binos. I have taken on board the comments from Raymond & Malcolm about learning the night sky so I am going to go looking for interesting features and push or drive myself to them. Then I'll use the goto to track them. It was really rewarding tonight doing that so I "get it"

Thanks

rustigsmed (Russell) · #20 12-01-2015, 09:47 AM

great choice, the SW goto dobs are fantastic