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Old 23-06-2015, 09:04 PM
Alasdair
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Getting closer to actually buying...

I first asked about buying a telescope some months ago, then temporarily put that idea aside: work was too busy, and the skies (in Melbourne) were cloudy, or it was too bloody cold. However! I have a birthday coming up, and my wife has promised me a telescope - which I'll actually buy myself - and family finances being what they are we've agreed on a budget of $1000.

Portability will be the thing: it will live in a backyard shed, and be brought out for observing.

I notice that Andrews Communication are selling a SkyWatcher BD 150x750 "with EQ3 mount and dual axis motor drives with hand controller" for $799 which seems like a very good deal, unless the mount and drives are cheap and nasty. Quite frankly I'd rather get a solid mount without drives than a wobbly mount with drives. They're also selling a SW BD 200 x 1000P (8") OTA "with the Bresser EXOS2 strong equatorial mount and stainless steel tripod" for the same price.

I like the idea of spending a bit less than $1000 on the basic setup; then I'll have a few dollars left over for an eyepiece two, and a couple of filters.

However, I don't want to buy something to find it's wobbly, hard to set up and position.

I'd welcome any thoughts and advice!

Thanks!
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Old 23-06-2015, 09:58 PM
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barx1963 (Malcolm)
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Hi Alasdair!
Big question is what you are wanting to do with the scope. From your post it appears that it is primarily a visual scope as there is no mention of a camera.
While there is nothing intrinsically wrong with the setup you are looking at, and the EQ3 mount is from what I have seen, a fine basic EQ mount, my personal opinion is that that this sort of setup is not the best for beginner visual observers. The reasons are several but mainly you will be dealing with polar alignment, a mount that moves in a non intuitive way, the eyepiece can end up in all sorts of odd positions. Also this is not a go to system, you will still have to learn to navigate using this scope.
If you are primarily interested in visual, a dob is a much better bet. For the same $$ at Andrews you can get a 10" solid tube dob that will show much more and be easier to use. I can speak from experience as I went down the exact same path and wish that I had gone straight to a dob from the beginning!!
On the other hand you may be interested in imaging. Again, this sytem is not really suitable as an imaging system as the mount is way under spec for an OTA of that size. As I am not an imager I will leave it to others to give advice if you want to go down that path.

Cheers

Malcolm
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Old 23-06-2015, 10:19 PM
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Satchmo (Mark)
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The 6" refractor tube is fairly heavy -I would think that the EQ5 is the minimum kind of mount to mount it on . I concur with malcolm, although I would add that even an 8" Dobsonian would be very handy and portable - and will give views of the Moon and planets far superior to a short focus 6" achromatic telescope.
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Old 24-06-2015, 01:03 AM
ausastronomer (John Bambury)
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Quote:
Originally Posted by Satchmo View Post
The 6" refractor tube is fairly heavy -I would think that the EQ5 is the minimum kind of mount to mount it on . I concur with malcolm, although I would add that even an 8" Dobsonian would be very handy and portable - and will give views of the Moon and planets far superior to a short focus 6" achromatic telescope.
Hi Mark,

That scope is actually a 6"/f5 newtonian. Notwithstanding that it's a short tube scope, I think the EQ3 is inadequate.

To the OP. I would be looking at an 8" dobsonian

Cheers
John B
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Old 24-06-2015, 06:22 AM
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ZeroID (Brent)
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8" or 10" Dob is by far the best bang for buck and easy to use start.
If it was just going to be shunted from shed to garden and you had the space to store and protect it then get the 10" and enjoy the view.
There not much real difference in size between them. Even if you progress to other scopes and systems later the big Dob will always be dragged out for those big sky views. You might even find a good deal on classifieds on here as people upgrade.
If you do go down the DOB path then also buy a 20mm or 15mm (or both) GSO Superview Eyepiece(s). They are dang good starter EPs and good value for the price. They are still my favourite and most used pieces of glass after 4 years.
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Old 24-06-2015, 09:50 AM
Alasdair
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Thanks, folks - so dob it should be then.

Is the OTA of, say, an 8" dob mountable on an equatorial or motor driven mount, should I decide to go down that path later on?

I read somewhere that motor driven alt-az mounts have in many cases eliminated the need for equatorial mounts, if all you want is steady tracking for long exposures. As I understand it an equatorial mount means you just have to move one setting for tracking, whereas with an alt-az mount you need to move two.

And as possibly a very foolish beginners question, say I was looking at Saturn with the highest usable magnification on an 8" dob - how long would it remain in the field of view, and how easy is it to hand track such an object for visual observing?

Thanks again!
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Old 24-06-2015, 12:26 PM
raymo
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You have the wrong end of the stick. You cannot use an alt/az mount for
long exposures, due to a phenomenon called field rotation, which is why
mounts that can be used in both EQ and alt/az modes are becoming popular.
You can mount a Dob OTA on an EQ mount, as many have done.
With a manual Dob at high powers a target will stay in view for a few seconds only, and nudging it to keep an object in view becomes easier with practice.
If you are not wanting to do long exposure imaging in the foreseeable future, a motorised [Go To] Dob is a great choice because you get
decent aperture and motorised tracking [no more nudging], and exposures up to around 30 secs are possible. If you want to do ANY
imaging with camera attached to the focuser, you must make sure that
the Dob you choose has enough back focus for prime focus imaging. Many brands don't. Skywatcher ones do.
raymo
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Old 24-06-2015, 12:39 PM
N1 (Mirko)
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Quote:
Originally Posted by Alasdair View Post
And as possibly a very foolish beginners question, say I was looking at Saturn with the highest usable magnification on an 8" dob - how long would it remain in the field of view,
That is a more than reasonable question. I observed Saturn through an 8" GSO dob at the stupidly high power of 480 the other night. Saturn took about 25 seconds to cross the XO 2.5's 44 AFOV. I had never intended to use this eyepiece on a dob like that (too narrow, too much power) but thought stuff it I'll give it a go. Neither concern materialised. Saturn is a forgiving target though.

Quote:
Originally Posted by Alasdair View Post
and how easy is it to hand track such an object for visual observing?
That's highly subjective, so I might as well say it's easy because it is for me. Assuming the bearings don't stick or grind of course. Less power (no more than 400x recommended for 8"), or more apparent field of view than above, and it becomes even easier. The general consensus is to use as wide an eyepiece (AFOV) as possible for Hi power on a dob to minimise nudging, but that doesn't mean other eyepieces such as modern orthos won't do well.
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Old 24-06-2015, 01:14 PM
tileys
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Alistair,

I have an 8" dob and when I got an equatorial mount I thought I'd just mount the OTA on it. It did work although it felt a bit unwieldy and a couple of times the gears protested a bit (prob a bit unbalanced too).

Soon after, I got an offer I couldn't refuse to buy an f/4 8" Newtonian reflector so I got that and put that on the mount instead and put the 1200mm OTA back onto it's Dobsonian mount.

I did like the simplicity of the Dob for viewing but found star hopping to be confusing and I was impatient and so looked into a goto mount (the EQ mount I now have). I have started to get into imaging now and am glad I went with the shorter tube for that reason. I tried taking photos using the dob (I don't have an argo-navis for it) and found it to be frustratingly difficult and imprecise, particularly since it did not have enough back focus (it's a GSO not a Skywatcher reflector).

I think, like many, I was unrealistic about what I could actually see visually from a suburban garden (with only the occaisional dark sky trip) - we are all a bit spoilt by hubble Imaging goes some way towards closing the gap on that expectation in that you can start to take pictures approaching what you may have been initially hoping to see visually.

In short, for lunar, planetary and brighter clusters and nebulae I think the views are very rewarding with a dob, but if like me you're a bit impatient you'll want to move on from that to an EQ (or fork) mount and a different OTA.

Of course - then your budget starts to get stretched...
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Old 24-06-2015, 01:42 PM
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Camelopardalis (Dunk)
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My opinion is that you should think hard about what you want to do first in the hobby before spending the cash.

The reason I say this is that many of us have multiple scopes for different purposes, visual or imaging, etc and I feel it's important for you to buy now what will be a catalyst for your enjoyment of the hobby going forwards.

Personally, I could look at the planets and the Moon and brighter objects that are visible from suburbia every night of the week if the weather would cooperate. It never gets old In which case an 8" Dob would serve you well and leave you a little left in your budget for accessories.

Don't get too hung up on high magnification...those nights are not the norm and you'll have built up experience and will have learned to deal with it when the time comes.

If you're more interested in the imaging side, decide what sort of imaging you'd like to do. You can get started with wide field using just a camera and a lens. A tracking mount lets you take longer exposures. Then you can add a small telescope for zooming in, and then additional scopes to increase the focal length to tackle smaller objects. The universe is your oyster!

Almost everything in this hobby involves opening our wallet...space travel costs money
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Old 24-06-2015, 02:43 PM
Alasdair
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Many thanks again. My interest is primarily visual astronomy: moon, planets, DSOs, the open bedroom window in the next street (just kidding!), but I also don't want to cut myself off from the possibility of a little imaging. The thing is, if I see something particularly nice, it'd be nice to have a snapshot of it.

Now I'm sure you're all thinking ; the man's a fool; he doesn't know what he's getting into - and of course that's largely true. I am a happy idiot.

However! I have written two books on digital image processing: you can see one here:

http://www.amazon.com/Introduction-D.../dp/0534400116

and it would be nice to leverage that expertise, such as it is, into some elementary snaps of nice stuff seen through a telescope.
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Old 25-06-2015, 12:54 PM
Alasdair
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I'll be ordering a Skywatcher 10" Black Diamond collapsible dob. Seems like the best balance of price, portability, usability. And it turns out you can do a little imaging with such a beast, as long as you are quite clear of the limitations involved. (Long exposures, for example, are out. Planets, at least Mars, Jupiter, Saturn, are quite do-able).

Thanks for all your advice and support!
--
Alasdair the astronomical idiot
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Old 25-06-2015, 06:53 PM
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barx1963 (Malcolm)
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Quote:
Originally Posted by Alasdair View Post
I'll be ordering a Skywatcher 10" Black Diamond collapsible dob. Seems like the best balance of price, portability, usability. And it turns out you can do a little imaging with such a beast, as long as you are quite clear of the limitations involved. (Long exposures, for example, are out. Planets, at least Mars, Jupiter, Saturn, are quite do-able).

Thanks for all your advice and support!
--
Alasdair the astronomical idiot
Good choice! While I usually recommend and 8", largely because I am conscious that most beginners have budgetary constraints, the 10" is a scope that will help you see more and is still easy to handle. A 12" starts to be a big commitment in space and effort!

Looking forward to hearing how you get on.

Malcolm
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Old 25-06-2015, 07:31 PM
raymo
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Good decision. If you come into some money later on, you can upgrade it to a Go To scope.
raymo
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Old 26-06-2015, 03:54 PM
Alasdair
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Good decision. If you come into some money later on, you can upgrade it to a Go To scope.
raymo
Ooh I don't think I'll ever come into that amount of money...

Funny thing, I was hunting around various shops looking for the beast, Andrews Comm were selling it last week for $899. Having decided to buy one - their price has suddenly jumped to $999. Ain't that just the way of things. "Don't pay $999 in Melbourne!" their website still advises. Anyway, a local Melbourne crowd will match that price, and I'd rather buy locally than trust to AusPost or whatever delivery company is used. So I'll nip out on Monday for it.

So - entry-level dob today, Takahashi 8" refractor on equatorial pier (a snip at about $220,000) tomorrow!
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Old 26-06-2015, 06:07 PM
raymo
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Nothing entry level about a 10" dob; they keep many people happy
for years. As Malcolm said, the 10 is really the top end of easily
transportable scopes.
raymo
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Old 26-06-2015, 07:18 PM
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acropolite (Phil)
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Excellent choice.
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Old 01-07-2015, 06:39 PM
brian nordstrom (As avatar)
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great decision , I have a 10 inch back in NZ and as Raymo says this is a serious telescope and you will get many years out of it , baring a catastrophe , on a side note. , a fellow IIS,r here in Perth has the SW 10 inch and no bull it has some of the best reflector optics I have ever seen. , very. , very good .
Enjoy yours , sure you will..

Brian.
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Old 01-07-2015, 06:56 PM
Alasdair
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I'm looking forward to it. I have actually bought it for my wife to give to me on my birthday (which is this Sunday); currently it's sitting in its cardboard boxes under a rug in a corner of the room, pretending not to be there.

The wait is in fact not a problem as I have an infinity of things to get done between now and then.

I also picked up the Celestron Astromaster box of eyepieces and filters, and I might see if I can find a shroud for the tube - or make one.

I would expect that as of Sunday there'll be about a month of heavy cloud and rain - that's usually how it goes?
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Old 02-07-2015, 01:44 PM
inertia8 (Australia)
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I was wondering why this week has been clouded out... if you don't mind me asking, from where did you purchase the Sky-watcher in Melbourne?
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