what 8 inch dob should i buy?

[SurferSmyth]

Hi guys im new to the whole amateur astronomy thing, but after a bit of research and some viewing at gin gin observatory, i have narrowed my first scope down to an 8inch dobsonian. heres what ive been looking at and what one would you recommend?

SkyWatcher 8" Dobsonian Telescope SW680

Saxon 8" Dobsonian Telescope

Bintel BT202-B 8" Dobsonian


with the skywatcher and saxon are they identical just rebranded?
and feel free to recommend any others that i can buy in aus

PS. why is it so hard to get a wide variety of different brand scopes in aus like orion ect!?

cheers in advance!!

[CJ]

Check out the Andrews Communications GSO 8" Dob. They are including a bonus 2" SV 30mm EP AND a pair of polarizing filters too, all for $449.

[PSALM19.1]

Welcome, and congratulations on deciding on an 8" Dob! I have the Bintel 202 and really really enjoy using it! Beautiful views of Moon, Jupiter, Saturn and Venus and also you can see Uranus and Neptune (of course, there is not alot of detail there, and it is NOT easy to find them!) I sincerely doubt that you'll have much problem with any of the scopes you mentioned and they will all perform well. Enjoy! :)

[noeyedeer]

I would recommend the gso from Andrews as well. the bintel one is just a rebadged gso .. with a few extra dollars ontop.

I wanted a lightbridge originally, but couldn't justify the price difference when they're essentially the same mirror.

either way .. it's a good choice, the 8". you will be happy with whatever you decide.

matt

[barx1963]

The 8" dob is a great starter scope. There are a number of variations.
Saxon and Skywatcher are both made by Synta. Saxon is the cheaper version. As also stated earlier the Bintel scopes are rebranded GSO ones.
When looking at Bintel vs Andrews there are a couple of things to remember. Andrews will simply ship the boxes as they arrived from Taiwan to you, that is not a criticism, I bought my 12" from Andrews while I believe that Bintel check and assemble the scopes before shipping.
When looking at price consider the accessories, usually the differenes are in the eyepieces supplied, but bea in mind it is unlikely you will use any eyepiece shorter than 15mm much if at all!

Malcolm

[Pete53]

I have a Bintel (GSO) 10" Dob. Came all set up and ready to use. Good service from the guys there and they really know their stuff. See Don or Michael, they will give you good advice.
Peter

[Marios]

I agree the GSO has come along way, the eyepieces I recieved with my 8inch were so much better than the standard Skywatcher ones I had with a previouse DOB. :thumbsup:

[SkyWatch]

From my experience both Bintel and Andrews give good service and know their stuff.
Regarding your question re other brands- Australia is not a big market, so we don't have the variety that they have in say the US. We do pretty well though, and most of our suppliers are competitive. (Besides which, a lot of scopes are made by the same factory, but simply re-badged.)
Bintel do stock Orion scopes, but most are the computerised versions which are more expensive.
BTW, Astronomy Alive have the collapsible Saxon dob if you want to fork our another $50 - $100 for ease of lugging it around or putting in the car. (http://www.astronomyalive.com.au/advanced-level-telescope.html)

You cant really go wrong with any of the 8" dobs as a good value scope.

Have fun!

- Dean

[astronobob]

quite a few considerations to make hey, , all good advice above :thumbsup:

Just adding that when choosing scopes, another consideration is what you want to mainly observe with it also. now, if you have good dark skies and wish to observe faint objects, like nebulae and distant galaxies, then, what we call a 'fast' scope is more suitable. the so called 'fast/speed' of a scope is determined by the F/Ratio of the scope, ie, an F/Ratio of 4 or 5, classified as F4 or F5 respectfully and are fast scopes which are best for faint nebs and galaxies etc, hence the need of reasonably dark skies, eg, relatively outer suburbs or country areas. tho if in the brighter subburbs, you may still see a few of the brighter nebulaes, but will struggle with hunting galaxies :thumbsup:

On the other hand, some newtonians are classified as 'slow' scopes, meaning an F/Ratio of 7 or 8 - F7 or F8 - now these will struggle with nebulae and galaxies even in darkish skies, but the will do much better than the F4 or f5 scopes at viewing bright star clusters, planets, moon and with a solar filter, do a great job on the sun, but yeah, only ever look at the sun with proper solar filters, rather rewarding actually, plus you dont need dark skies for these slower scopes when viewing the above mentioned bright object, planets etc :thumbsup: Being a slower scope does not mean it is inferior to a fast scope, because they are designed for this type of visual observing, planets moon star clusters etc :thumbsup:

Now, the F/6 ratio scope is in the middle and is what is probably the most popular as it is indetween a fast and slow scope, so its designed to get a bit of both worlds, a general good all round scope ! !

Newtonian = the actual scope, tube & mirror design
Dobsonian = the base that the newtonian scope sits on !

Hope this helps ?

[Camelopardalis]

Sorry Bob, I disagree...the 'speed' of a scope is not relevant for visual observing, besides being a factor of the focal length...a longer focal length 'slow' scope will have a maximum smaller true field of view with the same eyepiece than a shorter focal length 'fast' scope. The number of objects where this makes a significant difference is relatively small. What's most important for the fainter stuff is a darker sky.

Anyhow, what I'm saying here is irrelevant too because all the mass-produced 8" Dobs seem to be f/6 :lol:

[astronobob]

Crypeeze,
Funny, you have agreed to everything i mention, but you just explained it in a different way, and adding in EP's to confuse the issue, I am just keeping it basic for Ryan :thumbsup: What I dont understand is why you say that the speed of a scope is irrelevant ? of course its relevant, if you want a rich wide field view showing nebulae, then a fast scope is the go, in turn, if you want a clean well focused, magnified view of a planet, then a slow scope is needed, common knowledge mate ! Lets not take this any further :rolleyes:
Thanx

:fishing: :whistle:

PS, sorry Ryan, just thought to offer my 2 bobs worth ;)
Cheers !

[Camelopardalis]

Potato, tomahto :lol:

But not quite...the important distinction is that it is the focal length of the telescope that determines the maximum field of view, not the focal ratio. Whether it is fast or slow is irrelevant. Both an 8" Dob with 1200mm focal length (f/6) and a 100mm refractor with 1200mm focal length (f/12) will be capable of showing the same maximum FOV, yet one is faster and the other is slow :thumbsup:

Also, the eyepiece IS important as that is what brings the image to focus for our eyes :eyepop: and the focal length of the eyepiece and telescope together determine the magnification (magnification = FL telescope / FL eyepiece). For all intents and purposes, an 8" Dob is just as capable at showing a decent planetary image as a similarly sized Mak, they just get there in different ways.


Sorry Ryan...of the 4 choices available, they only come from 2 sources, Skywatcher (and Saxon) and GSO (and Bintel) :lol: to complicate it further, some of the Orion scopes are variations on optics from Synta (parent company of Skywatcher), so besides local rebranding of these, these are pretty much your choices in most places around the world. The exception (there always is one!) is any kind of custom built or boutique scope, but these would be much more expensive...

Anyhow, the best thing I can suggest is, if possible, get hands on with one or more of them to get a feel for them...either in a store or at a club or society or local meet.

[MortonH]

I think any of those 8" Dobs would serve you well as a first scope. There's not much real difference between them.

I had a Bintel/GSO one before and was very happy with it. Good optics, sturdy build, and cheap. Got mine for around $350 used.

[SurferSmyth]

First of all thanks Everyone for your feed back! really helpful!!
I was almost dead set on buying the Bintel scope until I found out it cost and extra $130 to ship it to Perth (650 total) after further research I found a telescope shop in Perth around the corner from my work! turns out there shutting down on Saturday and they have some good deals on and now im seriously considering a
SkyWatcher Black Diamond 10" Collapsible Dobsonian Telescope
what are your thoughts guys? no harm in going up a size but will I notice the difference?

[noeyedeer]

hi Ryan, as anyone would say aperture is key and if you can afford the extra 2inchs then by all means do it. you're not going to lose anything but ALOT more light to gain. (the 10" has 1.5 times the light gathering then the 8", using redimentry formula(10^/8^ 100/64=1.5625))

go with the 10", it's sad a lot of shops are closing thou.

matt

[SkyWatch]

If you can get the 10" for anywhere near the price of an 8", go for it! The collapsible dob will make a big difference if you want to transport it as well. A very nice scope. :thumbsup:

[Terry B]

Sorry Bob but it isn't "common Knowledge". The "speed" of a scope makes almost no difference to the brightness of what you see "visually". Photography is different but this is mostly moot with a dob that is designed as a visual scope. Aperture changes the amount of light you collect not the focal length of the scope that determines the f ratio.
Your description of seeing galaxies and nebulas is the same except for the very largest objects and the only one that I can think of that will fill the field of my f8 200mm scope is the andromeda galaxy. You just use a longer focal length eyepiece. :)

[Camelopardalis]

+1 for going larger, it's a slam dunk at that price :D

[MortonH]

Go the 10" collapsible - these are good scopes.

[SurferSmyth]

i got the 10"!!!!! and i love it i had a great view of Jupiter and the Orion nebula last night

[astronobob]

Agree with going the 10" Ryan, as mentioned the larger aperture will be more rewarding for sure :thumbsup:






Ok Ok :cool2: I understand what you guys are saying, with EP's, FOV's ect.
Tho lets look at this situation ?
Hyperthectically, there are two scopes. 10" F10 & 10" F5

Between these two scopes you have 3 Eps, 5mm 10mm 20mm

10" F5 with each Ep gives magnifacations of 250, 125 & 62.5 respectfully

10" F10 ______________________________ 500, 250 & 125

What gives :question: Go out and buy another Ep : say either a 2.5mm ( Hyperthetically) or 40 mm so the other scope can catch up :P but depend on which extremity - the other scope will out perform, yep, More magnification on a Planet or wider FOV for vast areas of Neb , ,
Why else do Planetary Imagers/observers get better results using Smit Cas F10's ect and Galaxy hunters/imagers prefer faster scopes. Look at Mike Sedonio images collected in just one night compared to Mega Data :rofl:
Whether imaging or visual observing, Tomatoes, potatoes carrots and garlic - may as well stick some big wheel on my mini minor and go 4x4 mountain climbin' on the other hand, grab the semi trailor and go briz city shoe shoppin :rofl:
thats the way I see it :thumbsup:

[barx1963]

I think what Terry and Dunk are trying to put across is that there is a strong myth that has developed in some circles that a "fast scope" is better in terms of making a brighter image when used visually. So that will put the idea in some peoples head that you can substitute a small aperture fast scope for a large aperture slow scope. Or in other words an f5 is always "better" than a f10.
From a visual observing point of view that is simply not the case. A 10" scope is still a 10" scope and will put exactly the same number of photons on the focal plane regardless of it's focal length.
That is why I think it is very important when talking to beginners that we explain carefully what is meant by the term "fast" and "slow".

Malcolm

[Terry B]

Bob
You said the very important word above. "Imagers"
Visually it is makes little difference. Have you ever looked through a 2.5mm eyepiece?
They are not easy to use and are very expensive.
Galaxy hunters always use big scopes. The speed is just a convenience thing. An f/8 18" scope is might tall.
Cheers

[astronobob]

I understand & have agreed with the EP situation, what is being said is indeed true, the resulting FOV & the brightnes of sky viewed with a certain aperture, whether be and F5 or F10 providing the appropriate EP is giving the same FOV, then the brightness will be equivelent, correct :thumbsup:

What I dont understand is why are yous exercizing against me and Not seeing my point ? Be a little more BroadMinded fellas, I wasnt born yesty, in fact I was grinding & pollishing my own Mirrors, building Tubes, 2ndary spider cells, main mirror cells and home made focusers and putting all these together etc 15 odd yrs ago !
This thread is Ryans and Ryan asking for advice, true ?
If I was in need of advice, I would have also asked for it in another thread !
I have agreed to what your points are, so lets just leave it at that :thumbsup::stupid: & I also agree with cheerful whistling :whistle::whistle: :P