What 8" Dob to buy ?

[UFO]

Hi Mal,

Yes, Andrewscom changed their info on the 8" GSO yesterday.
Now it will be Oct/Nov and the price has gone up from $429 to $499.

It makes Bintel price more attractive ($429).

I actually posted similar question on the day as you so I running 2 threads
http://www.iceinspace.com.au/forum/s...ad.php?t=34608

Do you know what comes with the 8" Skywatcher? 10:1 focuser, right angle finder etc? When I called BTOW they said the 8" is over $500.

[hikerbob (Bob)]

I got the older model (non collapsable) 12" Skywatcher from Andrews. Service was great and that was when delivery was free. It's a gem but could be improved on. The straight through finder is a pest and I've swapped the tension handles for some furniture adjusting bolts as I was often knocking the scope off target when looking high in the sky.

At home I use a laser pointer for most of my finding activities (Argo Navis is still a way off yet unless unforseen fortune comes my way). The laser works remarkably well in conjunction with The Sky software.

I've dealt with Bintell on some smaller stuff and have been very impressed with the service, both times I've ordered via the web and had phone calls to confirm that I had the order right (did you really want two of those?).

Once I got settled with the scope I gained the impression that I might have been better served by spending a bit more and getting some of the accessories first up (stuff the GSO has already) but I don't think thats a biggy.

The skywatcher is great for the money and has given me many hours of pleasure. I'm hoping that Skywatcher (or someone else) brings out a retrofit flexitube kit. The idea of being able to shrink a hot water system sized telescope down to drum size for transport is very appealing and feedback so far suggests that the flexitube is rigid enough.

Bob

[Fisherman (Mal)]

'Goodaye' Hiker Bob & UFO,

Skywatcher 8" features. I'm told a 10:1 Crayford focuser, a Pyrex mirror (not mentioned in the website?), 9x50 finder scope (straight through!), 25mm and 10mm EP's. $499. No freight charge as in Perth. ( but... they talk badly of the other brand when I know there probably as good. Poor selling...I don't like that.)

I just spoke to a chap at 'Bintel'. re their BT202.
They are a rebadged GSO with full instructions, 10:1 Crayford Focuser, R/A Finderscope, 15mm and 9mm Plossi EP's, and a moon filter and they reckon they do a 'pre delivery check!'
He was full of practical and helpful advise and very plesent to deal with. The freight cost though is $85 unfortunatly but their scope price is very good, as you mentioned UFO.

I'm waiting for a reply to an email from one other retailer?

Thanks for the info Bob, all very interesting

Getting close now ............very close

(Good fishing)

Mal

[dannat (Daniel)]

Mal, i personally think if you are starting out there is something tobesaid for buying local - just in case you need advice
Also getting a don shipped isn't cheap & can add up.

RE the ep's he gso might have more and be slightly better but just about all ill upgrade to something better anyway if they continue to observe

i think most place a high emphasis on the focuser, usually crayford with 10:1 fine focus being sought after: i have a regular crayford 1:1 & i get by with focus fine & don't think i will upgrade - seeing as how they both have 10:1 i would personally prefer local

[PCH (Paul)]

Originally Posted by UFO

Hi Mal,

Yes, Andrewscom changed their info on the 8" GSO yesterday.
Now it will be Oct/Nov and the price has gone up from $429 to $499.

It makes Bintel price more attractive ($429).

I actually posted similar question on the day as you so I running 2 threads
http://www.iceinspace.com.au/forum/s...ad.php?t=34608

Do you know what comes with the 8" Skywatcher? 10:1 focuser, right angle finder etc? When I called BTOW they said the 8" is over $500.

Yeah, - but BTOW will more than match on price if you tell him you've got a better price elsewhere. He's keen to do business wherever possible like all of them.

[UFO]

Hi Mal,

I also called Bintel this morning and he gave me the same freight cost $85 which pretty good for a big item 4000kms away. He also said it includes insurance.
They also check and laser collimate it before shipping.

Taken into account freight cost for Bintel they are basically the same price.

Another option is to ask Andrescom if they can supply the 8" GSO with RA find and 10:1 fine focus but I think the price will be pretty similar.

I wonder if anyone here has tried or own both GSO and Bintel. It would be great to have their opinion as to which one we should go for.
I personally wouldn't think we will need too many advise from the sellers except when buying it. We have enough people on this forum that can help us.

A couple more questions:
According to what I can find here pyrex is not that important for 8" reflector? Perhaps someone can clarify?

Plossl Eyepiece is better than no Plossl? Is this so? Why is it?

Who are the guys http://www.telescopeshop.com.au/Dobs...er_Dobsonians/
They are in Myaree.

[wavelandscott (Scott)]

Originally Posted by UFO

Hi Mal,

I also called Bintel this morning and he gave me the same freight cost $85 which pretty good for a big item 4000kms away. He also said it includes insurance.
They also check and laser collimate it before shipping.

Taken into account freight cost for Bintel they are basically the same price.

Another option is to ask Andrescom if they can supply the 8" GSO with RA find and 10:1 fine focus but I think the price will be pretty similar.

I wonder if anyone here has tried or own both GSO and Bintel. It would be great to have their opinion as to which one we should go for.
I personally wouldn't think we will need too many advise from the sellers except when buying it. We have enough people on this forum that can help us.

A couple more questions:
According to what I can find here pyrex is not that important for 8" reflector? Perhaps someone can clarify?

Plossl Eyepiece is better than no Plossl? Is this so? Why is it?

Who are the guys http://www.telescopeshop.com.au/Dobs...er_Dobsonians/
They are in Myaree.

The Bintel and the GSO come from the same manufacturer (GSO)...I do not know if they use the same QA/QC standards or not but assume that they do.

As near as I can tell, the difference is that Bintel take each GSO scope out of the box, inspect/collimate it and put a Bintel sticker on it in their store...(I may be missing a few steps) but they do add value by checking things out before the box gets shipped to you...so at least when it leaves the store you know that there is/was a working scope inside.

How much value you place on that is up to you to decide. Additionally they are knowledgable and as mentioned earlier helpful with advice (they helped teach me to collimate my scope at their shop before I left for home with my first scope). That is not to say other shops aren't helpful too...but I have dealt with them and experienced their helpfulness on many occassions.

For an 8 inch scope used in Australia the Pyrex/not Pyrex debate is probably a bit much...either way the mirror mass needs to get to/near ambient temperature for the "best" views...as the temperature drops at night either will require time to catch up. That is why the high end astro-photo folks using reflectors often invest in active cooling systems. I've found a fan is enough for my own uses.

Are the co-efficient of expansion/contraction (or whatever it is called) different between the two materials, yes I am sure that they are. Is one better than the other...on a big mirror maybe, but I'm not sure I'm sufficiently skilled to notice the difference on an 8 inch mirror. Either will need sufficient time to cool...depending on where they are stored and what the temperature difference is (storage to ambient) this is likely to take more than 15 minutes in either case.

Plossl is an eyepiece design...there are many other design types. The plossl design can and does come from different manufacturers...each with their own set of QA/QC systems... The best design may be dependent on the scope you intend to use it and the purpose you have in mind. People can and do write books comparing/contrasting the advantage and disadvantages of the different eyepiece designs. Again that debate often gets above my needs. In general terms, a plossl is a pretty good all around eyepiece design that when matched with appropriate QA/QC at the manufacturer level are often good work horse eyepeices...

My two cents...Clear Skies,

[erick (Eric)]

Originally Posted by wavelandscott

Plossl is an eyepiece design...there are many other design types. The plossl design can and does come from different manufacturers...each with their own set of QA/QC systems... The best design may be dependent on the scope you intend to use it and the purpose you have in mind. People can and do write books comparing/contrasting the advantage and disadvantages of the different eyepiece designs. Again that debate often gets above my needs. In general terms, a plossl is a pretty good all around eyepiece design that when matched with appropriate QA/QC at the manufacturer level are often good work horse eyepeices...

My two cents...Clear Skies,

My experience of the plossl design is that once you get down to 10mm focal length or lower, the eye relief becomes a very small distance and you'll have your eyeball pushed very close to the eyepiece. 15mm and above are fine - I love my 20mm Televue plossl. So for these shorter focal lengths, it's worth comparing other designs, eg. the Vixen LV, the various non-plossl Televue, the Pentax and lots of others.

[UFO]

Thanks guys for the info.

Mal,
I went to the lunar night. The place (car park) was pretty bright.
They only have the 10" Dob and it was good.
The price that he quoted you for the 8" does not include 10:1 fine focus.
The next 8" stocks will arrive on the 15/08 as you mentioned.

Personally I find that telrad will be of a very good help for a beginner like myself. Even aiming at the moon is not that easy
Also I find the telescope movement is not as smooth as I thought it would be. But I probably will learn to make small movement easy enough.
I think a right angle finder will be more comfortable to use.

[erick (Eric)]

Originally Posted by UFO

Also I find the telescope movement is not as smooth as I thought it would be. But I probably will learn to make small movement easy enough.

They are relatively cheap scopes with most money in the optics, not in the mount. But fairly straightforward to improve the movement for the average home handyperson.

[Fisherman (Mal)]

Hi UFO,

I think from what I hearing, telescopes are like many other products being sold these days, especially comparatively low priced imported ones. There are a lot of variables from model to model and it's buyer beware for sure !

I did beleive the Crayford focuser on the Skywatcher 8" was a 10:1?
I'm sure I was told that.

It's does seem a little surprising that a new telescope is possibly required to be modified to operate in an efficient way, when by its very design purpose this surely would have been part of the design requirements.

I guess you get what you pay for though. I would'nt be suprised if they were all (same models) a little bit different in that regard to.
Friction can vary with temperature.
The 10" would be heavier than the 8" maybe making it a little stiffer?
Is the base bigger to compensate for the extra weight ...I wonder?

To quote Eric "to improve them is fairly straighforward" ......but after spending $500 do you want to?

The million dollar question is, will the GSO be any better in that regard?

I'm hoping to get over there this weekend to have a look.

Many thanks to all for throwing in there thoughts on this one to....

Have a good weekend,

Clear Skys... (Good fishing)

Mal

[bmitchell82 (Brendan)]

Like it was said before, yes that is the million dollar question but look at it this way, it has only been in relitively recent times that ameture astronomers like ourselfs have been spoiled for decent size apperatures for decent prices. now if your where to get a 8" Newt on a decent GEM or Alt/Az your price jumps about 1500 ish maby less maby more add in good GO TO electrics.... you get what im saying.

So i look at it this way, get the best optical setup i can afford (re 10") if it sits on a milk crate and then i have to actually use my head and build something so it works ... so be it. The thing is that the main parts that i cannot build (have no idea) i can buy, anybody can go to bunnings and buy 50 bucks worth of tools and 100 bucks of materials to hitch up a mount... and should i mention the added enjoyment of saying to your family friends... I did this...

To emphisise my point further, i have taken part in the EWB challange recently, and their main point was everything must have a price value attached. eg... If you brought something out of the box that worked first time every time, would you value it as much as something that you have had to work for? or was added for free would you appriciate it as much as if you had to put it there.??

Thats my 2 bobs worth.... but on the upside, i get to play with curtin universitys gear! read Mead 200LXR 12" with SBIG Cam Laptops Series 5000 eyepeices a 40mm Hand grenade.! ahhh to have a institution willing to part with $$$...

[Fisherman (Mal)]

Hi Brendan,

yep... I understand what your saying and it can be good for many reasons to modify gear to suit.

In this case the decision is simple. It's one or the other.

There both value on the optics front.

Sounds like your spoilt rotton with the Mead 12" and all the fruit

Its great to get so many educated opinions on the subject through the website. I've learnt alot.

UFO....didnt get to BTOW's at the weekend. His business hours are quite restrictive for me. He must be doing really well to only open when he does.
I might open a telescope business in WA

How are you going?

Mal (Good fishing)

[UFO]

Hi Mal,

Yes, they close on Monday and Tuesday too.
I am still not sure. Maybe I'll wait for the new GSO 8" but I might change my mind in the meantime.

[Fisherman (Mal)]

Hi UFO,

I had a look at the 10" Skywatcher yesterday.
Looks a good, solid scope.
The Crayford focuser on that one is'nt standard is it (Bintell!).
It has a vernier knob adjustment which was explained as "really unnessasary".

The other extra was a 'laser red dot finder'. Which apparently makes life a lot easier finding objects in the sky. Another $80 or so . Yep...can live without one I'm told but ...................

I liked the general solid feel to it though and the adjustable altitude control looks good.

Being unable to look at a GSO with spring /friction control makes me wonder how good that could be ?.

Is there anyone out there that's got one of these and can tell me whats it performs like?

The turntable movement considering the weight I thought was'nt bad either.
So I'm told it can be improved on with a little work.

I wonder how good the GSO is on that count ?

Anyway, the 8" Skywatcher's should be in Sydney now and here by Tuesday.
I think they will be here when their here!

They 'may' also have R/A finders but won't know until they arrive and seen.
Imagine dealing with a supplier and your not sure whats going to arrive? 'LOL'

I will hang fire till I see the 8" Skywatcher.

Mal

[UFO]

Originally Posted by Fisherman

Hi UFO,

I had a look at the 10" Skywatcher yesterday.
Looks a good, solid scope.
The Crayford focuser on that one is'nt standard is it (Bintell!).
It has a vernier knob adjustment which was explained as "really unnessasary".


Mal

Hi Mal,
I was also told the same thing about the 10:1 fine focuser.
To be honest I probably can survive without one.
If you are still thinking about the 10" maybe you want to consider the collapsible skywatcher from andrewscom.

[hikerbob (Bob)]

Mal, I've used red dot finders and they can be good but a laser pointer is a lot better.

I've not used one but a lot of people seem to rave about Telrads as a finding device. They seem to be in the mid $70's (plus postage). From what I've read a better option than a red dot finder but I'm not speaking from personal experience. On the other hand what people really rave about (again I've not used one but have seen them in action) is the Argo Navis - unfortunately somewhat more money.

Cheers
Bob

[Fisherman (Mal)]

Hi guys,

I managed to get a look through an 8" Skywatcher Dob, a Mead Casegrain and a Skywatcher refractor last night. The conditions were'nt perfect as there was lots of stray light around.
The moon was like a 100 watt light bulb against the many 5 watters making it even harder!
It was interesting to say the least...and the moons craters very large and clear.

It was'nt a competition but other than it's inability to track the planets automatically the Dob won hands down for me.....

Beautifully simple, very clear optics and value for money, just about sums it up for a beginner like me.

The standard Crayford focuser, although not perfect, worked well enough. The EP's being used were not the standard ones but not super expensive ones either.

Bob, I saw a Telrad on one of the scopes. The owner was happy with it and I cought see the red sighting circles even near the moon. (just!)
The standard finders cross hairs were difficult to see against the night sky. I wonder if that could be modified?
Also without an R/A on the finder you had to be a contortionist to go to high altitudes. My back hurts!

UFO ...I will be happy with an 8".

So all in all, it was a very interesting hour .......

Mal

[erick (Eric)]

8" dob preferred - Yes!

Once you've used a 10:1 Crayford, you won't go back to standard - try to get one with whatever you buy.

Telrad or simpler red dot finder (last can be as cheap as $39) - both a form of "unit finder" or "1x finder" - both very useful items - Telrad is more sophisticated - susceptible to dew without some shielding.

Straight through finderscope - "my back hurts!" Welcome to the club! Yes, there are ways of providing some illumination of the crosshairs - usually involves add a dew shield to the front of the finderscope and illuminating the inside with a red led or two, thereby making the view of the sky a little lighter, against which the crosshairs become visible.

Right angle finderscope - yes, very good, but strongly recommend it is used in conjunction with a unit finder so you get into the right part of the sky before you look into the finderscope. There is a way of directing the straight through (by keeping both eyes open - one of the sky and one on the view through the finderscope). This cannot be done with a right-angle.

(Using a laser pointer is great, I do, but (1) laser law adherence and care needed wrt planes etc., (2) astrophotographers will come and hit you with bricks at a star party for ruining their image, and (3) dead batteries and you are lost, finderscopes always work.)

Happy purchasing!
Eric

[NeilW]

Hi all,

Do you know just what the "adjustable tension" on Andrew's new GSOs is or does, and is it useful?

Thanks

Neil