Andrews GS-680 Limited 8" f/6 Dobsonian

MintSauce (Gordon) · #1 15-12-2004, 10:58 AM

Andewscom is quoting me $399 for a GS-680 Limited 8" f/6 Dobsonian, with 4 eyepieces: 9mm & 25mm plossls and two more of my choice from the andrews 500 range. I was wondering if anyone thought this is a bad price (as I find it quite attractive) or if these scopes are not very high quality.

I was also looking at getting a SuperView GS 20mm and 42mm: Anyone got any opinions on these? or the Andrews 2" UW30mm 80 degree (which is not actually listed on their website).

Anyhow any feedback or opinons would be appreciated before I go ahead and order this.

Mint.

iceman (Mike) · #2 15-12-2004, 11:09 AM

Hi MintSauce, welcome to the forum!

That's a very good price for an 8" scope, there's several members of this forum who have that exact same scope, or the 6" or 10" derivative. I have the 10". Some of us got them from Bintel, others got them from Andrews. They are the same scope, imported from GSO in Taiwan. They are good quality for their price.

You'll be very happy with an 8" dobsonian, it's a great beginners scope and you'll see plenty of great things with it. It's portable and easy for 1 person to use and setup.

For the other 2 plossl's, I got a 15 and 32, it's up to you what other 2 you get, but you could also consider getting a 2x barlow. Perhaps you could ask for a discount on the SV eyepieces if you don't get the other 2 plossls.

Guys that have a lot of experience with eyepieces might have something to say about the SV 42mm and it's suitability in a fast scope, something to do with eyerelief and coma

Those with more knowledge than me will correct me. The same goes for the UW30mm - it has been reviewed on this forum and looks like a good eyepiece, though you can expect some coma around the edge of the field in a fast scope.

I'm considering getting the SV's or UW30 myself, i'm hoping to try before I buy, either from Andrews or maybe get a loan of one from someone else.

Good luck, you can't go wrong with a 8" dob at that price, many years of enjoyment to be had.

btw where are you from? How did you hear about the forums?

ving (David) · #3 15-12-2004, 02:03 PM

I have that exact same scope with the exact same deal... except back in march when i bought it it was about $500... go for it. the scope is great

I also got some small binoculars with mine in the package. dont know if they still do this but it doesnt matter if they dont cause its a great deal anyhow.

MintSauce (Gordon) · #4 15-12-2004, 04:10 PM

Thanks Ice for the welcome and thanks both for the replies I shall be ordering soon then I think.

Do either of you know if it's a 2" focuser on the 8" scope?

Mint

ving (David) · #5 15-12-2004, 05:02 PM

you get a 2" focuser and an adapter for the 1.25" eps

MintSauce (Gordon) · #6 15-12-2004, 05:46 PM

Thanks for that reply, I write more once I'm away from work

mch62 (Mark) · #7 15-12-2004, 06:08 PM

Hi Mint Sauce ,
Is this your first scope or Newtonian?
An 8" f6 scope is a great size to start with and will give you great views.
Most people are happy with these scope from Andrews and he does drive a good bargan.
The optics from the units i have seen appear to be quite capable.

If your new to astronomy, you don't want to spend heaps to have it gathering dust 6 months down the track if you loss interest .
An F6 is also easier to colliminate (align the optics) for your first Newtonian.

Have you read my review on this web site on the GSO 42mm.
I use it on my f6 newtonian and am suitable happy with it's performace.
With an f6 scope you will be however be on the limit as far Exit pupil diameter.
Meaning that a 42mm eyepiece devided by a 7 mm pupil size of a dark adapted eye will come to f6 the slowest practical scope.
Remember that the 7 mm will depend on age and may reduce to as low as say 5-6mm for the more mature observer.
What will happen in this case is you may see some central blackening of the image and what this is, is the diagonal shadow.
I am over 40 and did not find this a problem on my f6 but this is a personnal thing.

The 30mm may be an alternative to try and i find it also satisfactory in an f6 but this again this is a personnal thing as far as what you expect in the way of correction in a $150 eyepiece. There good if your after a bargan and can ignore the outermost aberations in the field. Yes they do give some distortion to the stars in the outer most 10-20% of the FOV but this does not bother me as i remeber that I am looking through a $150 EP and not a $700+ EP.
If your buying a $400 scope i think a $150EP is a good match.

I would not get both as the difference is on small as far as TFOV with only a small gain in magnification.

The 42mm is better quality but the 30mm gives that wonderfull field of view.

The 30mm is my favourite EP at the moment.

I would how ever recommend the 2"GSO 2X barlow for your scope.

Sorry for rambling on

Mark

Starkler (Geoff) · #8 15-12-2004, 06:44 PM

Buy it !

Its the best deal there is in Australia right now.
To be honest you cannot buy anything half as good at the price or even for a few hundred $ more.

I would however ask exactly what does "Limited " mean.

The eyepieces I was supplied with mine were Andrews branded, and are a bit average in quality, but at the asking price I would consider them to be a free bonus.

*warning* Budget for the inevitable future accessories, the assault on your wallet has only just begun !

MintSauce (Gordon) · #9 15-12-2004, 09:03 PM

Thanks guys.

to reply to ice before, I cannot remember how I stumbled across the forum but after a little lurking I thought I'd post when I was about to spend my money (so as not to waste it)
.

It is my first scope, I have 15x70 Binoculars which I find very nice but would love to look at more deep sky objects where a larger apature would help.
I was looking at getting a meade ETX105; but they are about the most I would like to spend, leaving no money for extras, and seeing as they are more suited to planetery observing this made me want a newt with a larger apature.
One other scope I was looking at was the Celestron 130 thingy with GOTO controller, but again quite expensive.
Then I saw the Orion 8" push to intelliscope; but they are hard to import (cheap in US tho).

Anyhow then I decided on a cheaper scope and I'll just spend the time to learn where to point it (I have a few objects that I like in my bino's already(had them a year now)).

I'm from scotland living in Kalgoorlie WA, where the skys are immense.

I fancy the sound of a very wide AFOV eye piece; so I think I'll get the 30mm GS one from andrews, and probably a barlow too.

Again thanks for the help, I'll keep posting with my progress.

Mint

Daring Dave · #10 15-12-2004, 10:41 PM

I think 'limited' might refer to a plate glass primary mirror rather than pyrex.... not %100 sure though....

Anyone?

Cheers

DD

Frosty · #11 16-12-2004, 12:05 AM

I just ordered that exact telescope (8" GSO Dob) from Andrews this morning, cant wait till it gets here

Cant open it till xmas, seeing as its a xmas present.

I got the 4mm and 30mm EP... I thought the 4mm would be good for planetary observations, hope im right :\

I believe the 30mm will be good for a wide view of the sky.

Though Im still a beginner at all this astronomy stuff, but im slowly learning

I just had a look through some 12 x 50 binoculars tonight and was amazed at what i saw.. i cant wait till i get to look through this scope.

Clear sky's ppl

iceman (Mike) · #12 16-12-2004, 06:17 AM

I think you're right DD, still, for the cost it's a great scope.

Great to hear you've order one Frosty.. the 4mm EP will be good for planetary and lunar detail, but will require better than average seeing to make the best use of it, and things can get pretty dim in those short focal lengths.

I got a 9mm, and with a 2x barlow gives me a 4.5mm, so you basically double your EP set with the use of the barlow, so it's best to choose the focal lengths that allow the barlow to be used to get the in-between focal lengths.

The 30mm will be good, it's a good low-medium magnification and will be great on deepspace objects, as well as full disc views of the moon.

Did you get to choose another 2 EP's?

You should try the binoculars more often, it's amazing the detail you can see, the expanse of stars and faint fuzzies that pop out.

Good luck and keep us posted!

MintSauce (Gordon) · #13 16-12-2004, 10:28 AM

ah well, I've just ordered it, the guy there seems spot on, very helpfull.

I got the 8" dobsonian with 9 &25 mm and 6.5&15mm eyepieces for $399
I got a superview GS 68 degree 20mm for $69
an Andrews 2" UW 30mm 80 degree for $149
and An Andrews 2" Barlow for $69.
plus free binoculars

(not that I expect them to be better than my 15x70's)
and to post it across the country it was $60, less than any other site wanted.
so that's $750 altogether. Very looking forward to it arriving; I'll let you know what eyepiece's are like and which get used the most.

Mint

iceman (Mike) · #14 16-12-2004, 10:36 AM

Excellent choices Mint, i'm sure you'll be very happy.. I like your eyepiece combinations too, i'm looking at the SV and UW carefully myself, so i'll be interested to hear your impressions.

Starkler (Geoff) · #15 16-12-2004, 10:36 AM

You will both love the 8 inch GS .

Frosty if its not too late I would drop the 4mm eyepiece. They are just too hard to view through. the eye lens is tiny and you almost have to push your eye against the glass to see anything.
For planetary viewing the best/cheapest bet is a plossl between 10-15mm and a 2x barlow.

If you cant get a barlow yet, I'd trade the 4mm for a 6.5mm if available.

First night out with it you may find using the finder a little difficult but after a few nights practise and it will become second nature.

A technique that works well is to have both eyes open looking toward the target, one of course looking through the finder and moving the scope until the images from both eyes merge.

MintSauce (Gordon) · #16 16-12-2004, 10:47 AM

I drew up an eye piece magnification chart to show the eye pieces that I wanted and what other choices were avalible if anyone wants a copy I can put here......not right now tho I'm off to work, cyas later.

Mint

Frosty · #17 16-12-2004, 10:56 AM

Yeah I think ill call em and let them know the 6.5mm would be better.

Frosty · #18 16-12-2004, 11:13 AM

Just called Andrews and changed both eye pieces... i ordered the 6.5 and 15mm which seems to be a good choice from reading through this thread.
Seeing as you get a 9 & 25mm EP's with the scope makes more sense to get these.

ving (David) · #19 16-12-2004, 11:20 AM

the difference between the 2 mirrors (as I have been told) is that the moer expensive of the two is more resistant to extremes in cold (which we generally dont experience here). other than that the image quallity is supposed to be the same, according to the guys at both andrews and bintel....

ving (David) · #20 16-12-2004, 11:23 AM

Quote:

Originally posted by Frosty
Just called Andrews and changed both eye pieces... i ordered the 6.5 and 15mm which seems to be a good choice from reading through this thread.
Seeing as you get a 9 & 25mm EP's with the scope makes more sense to get these.

exactly the same EPs i got

you will want a 32mm next tho :p