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Old 08-07-2017, 10:09 AM
Goro (Daniel)
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What to buy

Hi All

I've been admiring the skies for quite some time now and have decided it is soon time to get my first scope. I've been scouring these forums and others as well as numerous websites and can't go past the consensus that a dob is the way to go for a novice like myself.

My question is - I can afford to go as large as a 10" but was wondering whether an 8" might be more appropriate for me.

I don't want to travel with it - my backyard is pretty dark and the milky way is easily visible and detailed so I think I have some pretty good skies to view from at home (everybody is saying 10" at this stage, I know) but what I am concerned about is collimation. From what I can discern the 8" F6 would be a little more forgiving than the 10" F4.9. There is no astronomy club nearby so my likely brains trust would be your good selves out there on this forum when it come to learning this skill and if I get into trouble with it.
Is this a realistic concern or is it me overthinking the issue. I am reasonably technically minded so I think I will be able to work it out but I keep coming back to the other very common advice for people like me - the best telescope for me is the one that I'll use the most!

I want to see it all..... planets, DSO's and the moon but would really like something that impresses my primary school aged kids so that they want to spend some time getting into this hobby too.

Any thoughts/advice would be greatly appreciated.

Another quick question - are the bintel "brand" of dobs the same as the GSO brand of dobs available from Andrews, just with a different badge? or are they different somehow?

Thanks in advance, Dan
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  #2  
Old 08-07-2017, 10:21 AM
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Lognic04 (Logan)
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I would also recommend the 10 inch, collimation is really easy when you know what to do.
and as far as i know they are the same
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Old 08-07-2017, 10:43 AM
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Atmos (Colin)
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You are correct that collimation is more forgiving at F/6 than F/4.9 but not by that much. If travel isn't going to be an issue going the 10" over the 8" would be a good choice. That extra aperture will be worth it.
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Old 08-07-2017, 11:18 AM
raymo
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Just my usual warning to novices; if there is any likelihood that you may
want to take photographs through it, make sure that the Newtonian scope that you choose will allow this. Many do not, without being modified.
All Skywatcher [and Saxon, same scopes] Newts do. If buying another brand, check the scope's specs, or check with the vendor.
raymo
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Old 08-07-2017, 01:27 PM
Tropo-Bob (Bob)
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Most people will go for the larger telescope. but I would suggest the 8-inch scope. With the longer F ratio, the scope will be less troubled by coma, which is an annoying optical issue that degrades images. Also, any modern EP will work well at F6, but not necessary at F4.9.

The 8inch will also weight less, which means that it will probably be used more often. Use the money that U save to buy some good EPs, as the ones supplied with these scopes are somewhat basic.

U will probably be happy with whichever one that U buy, as the Dobs are outstanding value for money.
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Old 08-07-2017, 02:46 PM
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barx1963 (Malcolm)
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Daniel
Some good questions there and well done on taking the plunge in astronomy. Yes you are right the smaller dobs are definitely the way to go for visual work and are the best bet for "impressing" the kids as they can easily operated by a child but have plenty of oomph to keep you happy.
The Bintel dobs are rebranded GSO dobs. The main difference (as I understand it) is that Andrews simply ship the scope as it arrives to them. Certainly when I purchased my 12" it arrived in a box that showed no evidence of being opened after leaving the factory in Taiwan. Bintel I believe do check each scope and do a quick collimation on the OTA before sending them out. I am happy to be corrected on this last point if that has changed.
Collimation is often a scary subject for beginners and yes an f4.9 is going to be a little less forgiving than an f6 but not by much. My advice to beginners is have a go at collimating your scope as best you can but don't obsess about it.This hobby is for a lifetime, there is plenty of time to learn how to collimate to perfection if that is what "floats your boat".

Malcolm
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Old 08-07-2017, 04:07 PM
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Nebulous (Chris)
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Hi Daniel,

When this question is asked on forums the 8" Dobsonian regularly seems to top the poll. They offer very good bang for your buck, and you wouldn't be going far wrong. However, I would still recommend that you also check out a refractor telescope with an Altitude/Azimuth mount. They can be a very good starter choice too. You are wise to say that you are looking for your "first scope" and not expecting that one telescope will satisfy you for ever.

The first telescope I bought was an inexpensive 80x400 refractor Skywatcher and I still use it (it's now mounted on top of a Newtonian and used as an additional finder scope). The huge advantage of it, especially when I was a beginner, is that it shows everything "the right way up". Most scopes reverse either one or both axes, which can be confusing to begin with. When you're looking at a group of stars it may not matter much which way up they appear to be, but it can matter a lot when you're first trying to find your way around the sky and everything in view moves the opposite way to what you're used to. It also means that you (and the kids) can use it for daytime viewing of scenery, nature etc. without the image reversal problems.

They are very easy to set up - you simply unfold the tripod, point and look. Even the very simple Dobsonian mount needs to be set firmly on flat level ground and they have quite a large diameter. One of the big enemies of the amateur astronomer is any kind of wobble and vibration. As you say, you will at some stage need to collimate a Dobsonian - or at the least check that the collimation is OK - which does require learning some new skills. Laser collimators are a handy tool but do cost a bit.

As you said, the best telescope is the one that you actually use and the easier the initial weeks are, the more likely it is that the hobby will stick.. Another good purchase (for me anyway) was a finder scope with a right angle erector prism (aka corrector prism). It shows everything "the right way up" and also gives me a much more comfortable viewing angle. The ones usually provided are straight through and also reverse some of the view. When pointing the main scope upwards, it can mean getting into some seriously awkward positions to be able to see through the finder. It's also worth noting that the bigger the magnification, the harder it is for the novice to find their way around, because you can only see a tiny piece of sky which makes it very hard to find your bearings initially.

No matter how much you spend (within reason) you are really only likely to be looking at increasingly large clumps of white dots. You won't be seeing the Cassini spacecraft diving through Saturn's rings or much in the way of fine detail on anything except the moon. An important aspect of the hobby is the reading and study required to fire up your imagination and bring those white dots to life.

Whatever you go for will provide some successes and some relative disappointments, so don’t be too worried about getting it exactly right. Most scopes can pick up Jupiter’s moons and some version of Saturn’s rings, but they will be very small scale compared to the photos we’ve all seen. There’s always next year and your next bigger and better scope if the bug bites!

Good luck with your choice.

Cheers,

Chris
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Old 08-07-2017, 05:11 PM
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doppler (Rick)
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The best advice is always try and find a local astronomy group and have a first hand look at / through some different scopes if you can. What ever scope you buy you will wish you went a bit bigger, this is quite a common condition called aperture fever. Don't dismiss second hand scopes either, there are plenty of high quality scopes for sale if you look around. Coma and collimation are not a big issue for visual use.
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Old 08-07-2017, 05:47 PM
Dingers (Matt)
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Given that you're in Wagga and you'll have access to much darker skies than those stuck in the city, I'd really recommend investing in a Digital Setting Circle (DSC). This will make finding DSOs, comets, etc etc much easier.

I've got a Nexus DSC from a company called Astro Devices (http://www.astrodevices.com/shop/ind...ge/1/Nexus+DSC). I use it with the Sky Safari app on my phone and connect to it via WiFi.

It was fairly straight forward to install their Sky-Watcher encoder kit on my 10" dobsonian.

From there, it takes a few minutes to do a two star alignment and you have access to hundreds of thousands of objects in the sky!
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Old 10-07-2017, 07:47 AM
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sil (Steve)
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You will want to get some good quality eyepieces. If you think you may want to go bigger for those fainter targets rather than magnification then I say go for the 8". Later when you want a bigger scope or a different one for astrophotography or whatever it will still be a good size to use as a second scope anyway. 8 or 10 in wagga wont disappoint, but then again EVERY scope disappoints eventually, you can never have a big enough light bucket. Its the eyepieces that do the heavy work and the ones that you get with a telescope are at best "ok" and you will get a noticable viewing "upgrade" of clarity and contrast.
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Old 10-07-2017, 10:24 AM
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Visionary (David)
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It's said.... "Sailing is like standing under a cold shower and ripping up $100 bills".
As contrasted with Astronomy.... "Astronomy is like standing in the dark and ripping up $100 bills"
Welcome to the club, hug your significant other, tell her/him you love them and prepare them for "bill shock"!

Cheers
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Old 10-07-2017, 12:34 PM
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Nebulous (Chris)
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Quote:
Originally Posted by Visionary View Post
It's said.... "Sailing is like standing under a cold shower and ripping up $100 bills".
As contrasted with Astronomy.... "Astronomy is like standing in the dark and ripping up $100 bills"
Welcome to the club, hug your significant other, tell her/him you love them and prepare them for "bill shock"!

Cheers


So true...

The best advice yet.
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Old 10-07-2017, 02:02 PM
raymo
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I suspect that in this day and age of much cheaper, larger scopes,
most newbies would quickly get bored with the offerings of a small
refractor, especially a chromatically challenged achro.
There is a fine line between the largest scope that will continue to
get used, and one that won't, and several factors decide where the line is drawn; age, gender, fitness, interest level, and budget. My own line that I used to recommend to my newbie adult students was young, and fit,-- 8 or-10" Newt, according to preference, middle aged in normal health --8", and elderly or frail--6". There was nothing, of course, to stop the more involved ones from upsizing at a later date.
From my own experience of almost 70 yrs of using scopes of most commercially available types, I can safely say that if I could only have one scope [this applies to visual use, not imaging], I would rather have a
mass produced SW or GSO 8"Newt [or even better, a 10"] than the
finest 100/120mm APO refractor. For me aperture matters more than the
tiniest possible pin point stars. My last scope before I gave it all away
was 120mm, and my observing life went out with a definite whimper
rather than a bang. I understand that many refractor aficionados
would probably disagree, but each to his own.
raymo

Last edited by raymo; 10-07-2017 at 02:05 PM. Reason: correction
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Old 10-07-2017, 06:37 PM
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Nebulous (Chris)
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How’s the choosing going so far Dan? Nice and confused yet?

Typically, the answers you get on threads like this is a spread of other people’s preferences and experiences and they may or may not turn out to be directly relevant to you. The big difference between the new people asking the questions and the more established people answering them is that the experienced ones have a pretty good idea (with hindsight) as to how their own interest developed. But there are many different preferences and objectives, and the most suitable equipment for the tasks will differ too.

If you haven’t already read them I’d suggest checking out two excellent articles on this site, by Brian Nolan.

Part 1: General Principles for Choosing your first Telescope

http://www.iceinspace.com.au/index.p...63,260,0,0,1,0


Part 2: What’s wrong with each of my Scopes.

He covers the main choices - binoculars, Newtonians (either with or without a Dobsoninan mount), and Cassegrains. In his view, they all have advantages and disadvantages.

http://www.iceinspace.com.au/index.p...63,261,0,0,1,0

Good luck with the selection, and be prepared to buy more than one if the hobby gets a grip on you.

Cheers,

Chris
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Old 10-07-2017, 08:28 PM
raymo
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There is one negative point that Brian raises concerning Newtonians on
equatorial mounts that needs addressing. For either several hundred
dollars, or, in my case, $5, you can modify any Newt so that you can
have a comfortable viewing position no matter where in the sky it is
pointing. This makes it easy to use near or at the zenith, which is more than you can say for a refractor, unless you have a tripod three metres tall. I posted a pic of my D.I.Y mod in a recent thread here.
raymo
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Old 11-07-2017, 11:03 AM
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ZeroID (Brent)
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Daniel,
Go the 10", your eyes will thank you for it.
An 8" F6 is the same length as a 10" f5 (4.9) and weighs only slightly more. If you want to see more then aperture rules.

GSO Superview 15 mm and 20 mm EP's are relatively cheap and good value and they work well. They are my most used EP's for almost everything.
Get Stellarium on your PC ( if you haven't already done so ) and plan your viewing around what it shows you is locally viewable that night. Too early to get too complicated to start with, keep it simple to begin with and enjoy the dark skies you seem to have.
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Old 11-07-2017, 03:10 PM
Goro (Daniel)
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Thankyou

Well I'm astounded by the great responses. Thankyou.

Lots of good advice given. I guess I'm still leaning towards a dob despite a couple of convincing arguments for a refractor and now think that a 10" is the way to go, as it seems that my concern over collimation might exist just as easily with an 8" with little difference in the two. I'm sure I'll get the hang of it though....with practise! I still have a bit of time before I make up my mind - I tend to labour over purchases such as this for quite some time before I make a decision.

I'm not interested in astrophotography.....yet and by the sounds of it may need to get a second and third job if I go down this path but at the moment just want to get myself and the kids looking up at the stars. One of the fond memories I have as a kid was when my dad bought a telescope so that we could witness the passing of Halley's comet and the conversations we had about the universe as a result of this and I would love to emulate this with my children.

In the days since I've posted I can see that I might need to purchase a star atlas to get the hang of star hopping. I have stellarium loaded already and use frequently when I go out with the binos to try and pick out a few objects. Maybe this would be just as good as a star atlas??

Also the scopes I mentioned come with an 8x50 RACI would I need a Telrad as well or is this probably overkill?

So many questions. Like I mentioned in my original post there is no club near me (the closest is probably an hour and a half away) but I am lucky that there is such an awesome online community here.

Thanks again, Dan
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Old 11-07-2017, 03:22 PM
croweater (Richard)
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G,day Dan. A Telrad is not overkill. One of the best (and cheapest) accessories you will buy. Extremely useful when starhopping. Definately reccommended. Still probably one of the most used things that I have. Reduces a lot of frustration. Get one. Cheers Richard
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Old 11-07-2017, 09:44 PM
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Nebulous (Chris)
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Quote:
Originally Posted by Goro View Post
Lots of good advice given. I guess I'm still leaning towards a dob despite a couple of convincing arguments for a refractor and now think that a 10" is the way to go, as it seems that my concern over collimation might exist just as easily with an 8" with little difference in the two. I'm sure I'll get the hang of it though....with practise! I still have a bit of time before I make up my mind - I tend to labour over purchases such as this for quite some time before I make a decision.

It sounds like you've done plenty of reading and are aware of the various pros and cons of the different options.

That being so, then there's a lot to be said for just going with your heart. If the thought of wheeling out a 10" Dobsonian is what gets you feeling more enthusiastic than the other choices, then there's no particular reason not to trust your instincts. They're great value for the money.

You didn't mention whether you were considering a standard mount or a computer driven Goto? If you get a goto mount then of course navigation isn’t much of a problem! But if you go for the standard mount then any accessories that help you find your way around will probably be money well spent, whether that’s a Telrad or a good low powered finder scope that shows a relatively more manageable chunk of sky.

I can’t speak for others, but the thing that I found most difficult when I started was simply finding my way around. It all looked fairly straightforward when I looked up at the sky, or checked out something like Stellarium, but once I looked through a good telescope I quickly found out how many millions of similar looking white dots there are up there, and what a very tiny piece of it I was seeing through the telescope. And the more powerful the scope the smaller the viewing window was, and the harder it was to navigate accurately.

It took quite a while to develop the skills to recognise patterns, pick out the key features, and move smoothly in the right direction (in fact I'm still a long way from being good at it). It felt a bit like going to a guitar forum and reading about “easy songs” and “easy” chords when for a beginner there’s no such thing. They’re all hard for the simple reason that it takes months of practice before your fingers will accurately form even the most basic chord pattern. And then once you get the knack you tend to forget how hard it was at the start.

So don’t be too worried if it seems hard to find your way around initially. It gets easier with practice. Honestly.
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