What will I see with an 8' Dob

Shulgin (Aaron Raynor) · #1 12-08-2012, 08:36 AM

Hey guys,

New to the forum so firstly hello all ! Now that formalities are out of the way I am in need of some help. I'm wanting to buy (kind of an upgrade from a 5" Newtonian) a collapsable Dobsonian.

I'm thinking the 8" Saxon one from Ozscopes. I'm just wondering what in fact I'll be able to see with it, and in what detail, I've had a look on youtube ad some people who've taken images with there iPhone/webcam up against the eye piece but I'm of the mind that this wouldn't do it justice. I'm hoping that you can see Saturns rings with half decent detail and a nebulae or 2 would be awesome !

Anyway thanks in advance for your help,

Shulgin

Oh also I thought I should say that I'm after the collapsible because 1) I live in the suburbs of Melbourne so most of my viewing will be done after an hours car drive and 2) I dont want to spend over $600.

loki78 (Jon) · #2 12-08-2012, 08:59 AM

Firstly welcome

My first scope was also an 8" dob and I can tell you that straight away with the plossl eyepieces that come with it you will already see great views of saturn and its rings. This will be improved over time by adding better eyepieces to your collection.

You will see some nebula, but the thing to remember is you won't see them in colour like in all the pretty pictures.

But an 8" dob is a great place to start that will give you loads and loads of fun and plenty of things to see. I assume from your budget you're not getting a goto scope so you'll be manually controlling it, so get yourself some star charts to help you learn the sky and there are many free programs for your pc or apps for smartphones that can assist you in this area also. For example stellarium for the pc (and iphone i think) and apps such as sky safari or star walk to name a few off the top of my head for smartphones.

barx1963 (Malcolm) · #3 12-08-2012, 04:13 PM

Hi Aaron.
An 8" dob is a great starting point or as an upgrade from a 5". Personally the so;id tube is not so difficult to transport as it is the base that is the bulky part of these scopes. When I was using one I could fit the entire lot on my backseat, so don't be afraid to save some money with a solid tube.
You should see some nice views of Saturn with it, but it will not be a huge difference compared to the 5". Atmospheric seeing is the main factor in planetary observing rather than scope size. Having said that you will be able to get heaps more DSO's with the 8". All the Messiers will become available easily and many more objects.

Good luck with the purchase.

Malcolm

Shulgin (Aaron Raynor) · #4 12-08-2012, 06:26 PM

Cheers guys, Jon have an app for the iPad that works pretty well so should be easy enough.

And yeah I've heard that the atmosphere is the biggest problem, so any recommendations as to what eyepieces to get ?

Cheers

Aaron

loki78 (Jon) · #5 12-08-2012, 11:22 PM

That's a whole other kettle of fish.

Depends on a lot of factors, chiefly budget.

Then what do you like looking at, do you wear glasses when you look in eye pieces.

Plenty of the guys here have big collections and a wealth of knowledge so answer those questions first and they will be able to point you in the right direction. Nothing is a substitute for going to an open night/star party and looking in these eye pieces for yourself as it really is subjective. But that's not always possible so give us as much information as you can and the think tank will try to steer you a bit

Suzy · #6 13-08-2012, 01:47 AM

Hi Aaron,

Regarding eyepieces, I strongly recommend waiting a couple of months before doing anything. Asking what eyepiece to get is a huge question- unless you do a crash course in it's education, my advice is to hold off and get a feel for the equipment & eyepieces that come with the scope first, then you will have a better idea of what it is you want. There are so many factors not forgetting your budget that comes into it. When you are ready, have an extensive read through the eyepieces forum- go back as far as you can and read through the threads. Then you will be in a better position to ask that question I think.

Go the 10" dob if you can afford it. It's the same length tube as the 8", but the base is a bit bigger I think. Still not a problem though fitting in both into a med/large car. You should make sure it's going to fit before you buy just to be safe. I lay the tube on the backseat strapping the seat belts around it and the base goes in the back (or whatever fits best). Wheels attached to the base or a $20 trolley from Bunnings is helpful to move it around the yard as it's quite a bit heavier than the 8", but the views it will give will last you a long time before you feel the need to upgrade (if you do). I see loads of galaxies thru it from my light polluted backyard.

Also, if you get the 8" and decide to upgrade, you'd probably need to jump to a 12" to see a big difference. The upside is the 12" is also sold as collapsible & transport shouldn't be an issue, moving it around might be tho. Me, I went from a 6" to the 10" as thankfully the guys talked me out of making the small jump from the 6" to the 8" as I originally was going to. There was a huge difference in the Orion Nebula making that jump.
Having said all of that, an 8" is a popular size and known to show plenty of objects.

Perhaps you can meet up with a local astro club- I'm sure they will be more than happy to let you look thru their scopes.

Have a look at my target list for July/Aug here. Most should be observable in an 8" dob (except for the difficult section). Some may require a dark site, but many will be achievable observing through light pollution. Some good tips in there too if you keep reading thru the thread.

P.S. Saturn is a jaw dropper in a 6", so in an 8" it'll be amazing also.

ZeroID (Brent) · #7 13-08-2012, 09:55 AM

Hi Aaron and

Suzy is on the money there. If you can go 10" it is well worth the difference. As she says they are about the same length but a fraction fatter and in a LP site will make a diference as to what you can see. Nonetheless the 8" is a good size and you will see heaps.

Not sure what EP's will come with whatever scope you get but I built my scope so had to buy from scratch. The first two eyepieces I got were GSO Superview 20mm and 15 mm. The Superviews have a wider FOV (Feild of view angle) than Plossls and the GSO ones are not a bad price for the quality they give. They are still my most used EP's for nebula, globulars and the moon. They are a good starting point IMO with whatever your scope might come with when you get it.

andyc (Andy) · #8 18-08-2012, 04:06 PM

You'll see loads with an 8" scope! Even from a suburban backyard, you can find many dozens of interesting objects (as many as half of John Bambury's list of 600 southern objects with time and practice), and you'll see some great detail in bright objects like Eta Carinae, the Tarantula Nebula and many others. Lots of clusters will be rich with stars, and an 8" will begin to resolve many brighter globular clusters. Views of 47 Tuc and Omega Centauri are spectacular. Saturn will be beautiful, and you should be able to see the Cassini Division on many nights, as well as several moons (up to five?), and occasional details on the planet, like subtle cloud belts will be visible with time at the eyepiece. Ditto for Jupiter - Red Spot, main cloud belts, other cloud features, spots, festoons and barges. You'll have to wait a while for Mars to be big enough for a decent view (it's tiny just now), but once it is, in early 2014, the polar caps and some dark/light features on the planet in good seeing.

If nebulae are going to be your thing, I'd definitely recommend saving and getting a nebula filter (something like a "UHC" or "nebula" filter) - one that fits 1.25" eyepieces is ~$80-$130. In a light-polluted backyard, these work wonders on emission nebulae and planetary nebulae. With this, you'll see over a dozen patches of nebulosity in the Large Magellanic Cloud on a good night, many otherwise invisible details in bright nebulae, and track down fainter nebulae such as Thor's Helmet. Eta Carinae will extend well beyond the field of a low-power eyepiece! From a dark sky the views only get better of course.

From a dark sky, hundreds of galaxies are visible with an 8", but most will be faint puffs and streaks of light. Still, it can be a bit awe-inspiring to appreciate what these little smudges are, and just how many of them are out there. Filters don't tend to work well with galaxies.

So lots to see with an 8", and enough to keep you busy and excited for years

. If you can get up to a 10", the views will be better still!

Aidan (Aidan) · #9 18-08-2012, 04:44 PM

Google Sky map is free app.. The locations of most Messier Objects are shown on this app as well as planets, and constellations. It is basic but will help you navigate the stars it also has a night mode (red light) to not stuff up your night vision.

Hope you enjoy the new scope.

Aidan

moonunit (Joe) · #10 18-08-2012, 07:24 PM

Go straight to the 12".

Shulgin (Aaron Raynor) · #11 09-09-2012, 04:24 PM

hey guys,

Thanks for all the input, I ended up buying the 8", the minister of finance said no to an upgrade.... arghh. Oh well.

It will hopefully arrive on this coming Tuesday/Wednesday so I'll get it out one of the nights it's clear and will have a play. WIll have a look at Mars, Saturn and M83.

I'll report back.

Thanks again guys

Cheers

Aaron

erick (Eric) · #12 13-09-2012, 02:07 AM

you won't be disappointed with what you see. and easy to take places.

fauxpas (Tony) · #13 29-09-2012, 06:38 AM

I'm getting aperture fever, as they say, and been looking for the best deal per inch...

In 8" I think the bintel is the better option as it has a micro focuser, a fan and what looks to be a drop in base not a bolt in base... $499 + del http://www.bintel.com.au/Telescopes/...oductview.aspx

Personally I'm seeing if the 12" Meade Lightbridge will fit in the car... A 12" truss dob for $1099... I think its worth it as I know me, I'd be wanting more if I got an 8 or 10...

Suzy · #14 29-09-2012, 10:08 AM

Tony, as a rule of thumb- get the biggest aperture you can afford and transport. So if it ticks all the right boxes- get it- it'll keep you happier longer! If I remember correctly, I think the Light Bridges already come on wheels? Which is a bonus- check tho. I've seen video demonstrations of them and how superbly with easy they movie alt & azi. It'd definitely be my choice if I were going collapsible in a 12".

In my humble opinion and this is purely what I'd do.
I'd forget about all the fancy gizmos I could get with say an 8" (focussers, go-to etc). APERTURE is what matters- it's what will allow you to see more detail than an 8, and to me that's what it's all about. Then later on, I would do the additions to the scope, and that's exactly what I did with mine. I've upgraded the finder, added an Argo Narvis, drilled holes to accommodate a red dot finder as well, added wheels on the base, bought premium eyepieces, did mods to the base etc etc etc. All during the course of time.

Barrykgerdes · #15 29-09-2012, 05:18 PM

Quote:

Originally Posted by fauxpas

I'm getting aperture fever, as they say, and been looking for the best deal per inch...

In 8" I think the bintel is the better option as it has a micro focuser, a fan and what looks to be a drop in base not a bolt in base... $499 + del http://www.bintel.com.au/Telescopes/...oductview.aspx

Personally I'm seeing if the 12" Meade Lightbridge will fit in the car... A 12" truss dob for $1099... I think its worth it as I know me, I'd be wanting more if I got an 8 or 10...

If you are careful you can get a 16" lightbridge into a fiesta hatchback.

Barry