Saying Hi - First Post!!

[Dez]

Thanks for the info John!

I think at this stage I will be leaning toward the 12" LB as it just seems like it will be the most versatile compared to the solid tube type 12". I have a lot of trees in my backyard so I will want to travel with the telescope and if it's too much of a hassel due to the ATO being too large, the chances are it wouldn't happen very often.

Therefore, I think it comes down to either 12" LB or 10" GSO as both should travel ok. Mmmm... big price difference though, $699 vs $1499 advertised from one retailer... I understand they both use mirrors of the same maker, so technically shouldn't mean too marked a quality difference..

Is an extra 2" in a dob worth $800 (approx)?????? That's a lot of accessories..

Or maybe I could get two GSO 10", strap them together and have really big binoculars!!

Cheers
Dez

[norm]

Hi Dez,

I can't remember the percentage difference between the 10 and 12, its not as much if it were from 8 to 12. I'm sure someone will advise you on the stats.

I read it somewhere in the forum that if you go down the 12" LB path, the deluxe comes with a standard crayford focuser, which in itself is a very good focuser. However if you ask them to upgrade it to a 10:1 crayford focuser, you only need to pay the price difference, which is ~ $25. Worth spending as opposed to deciding to do a separate upgrade down the track, which will set you back ~ $100. Some some food for thought!

The 10:1 crayford gives you the ability to perform finer focusing. Seems a lot of people have gone this way over time.

[GrahamL]

both are good choices dez..I cart my 10" around a fair bit in a sedan
The views between the 10" and 12" ?.. yes I can see a differance
but it isn't huge ..one thing that i do find a pain is the base of the
gso and possibly the lightbridge as well is it is quite large.. the base of my 10 by a matter of cms wont fit my boot and requires dissmantling if I want to take somone with me.

good luck ..again both are great choices ,,thats a fair coment btw on the $800 .. its a couple of good eyepieces ,telrad, cheshire ..etc

[astronut (John)]

Hi Dez,
Correct!! The LB's and GSO's have the same optics, so it really comes down to portability.
Do you need to break down the scope to fit everything in your car?
Remember, you will be adding items to your observing gear over time.
E/p cases, batteries, 2 chairs one for observing and one just for sitting etc, etc..
A 12" solid tube will perform brilliantly, but (there's always a but)
it is BIG, I've seen one of our club members manhandling one onto an EQ6, he's 5' 6" it's an effort.
As you've pointed out there is a price difference.
Our club has an observing night this weekend, you're most welcome to come out and see for yourself. Let me know if you're interested, we're situated in Campbelltown.
Cheers, John.

[Paddy (Patrick)]

Hi Dez, don't know much but I know I like my 12" GSO. But I don't transport it except on a trolley out of my shed, I'd hate to lift it and it only just fits in the back of my camry wagon. I can't imagine putting it on a tripod and would get a second scope for astrophotography if I ever get into that. I don't know a lot about optics, but calculate that if light collected is proportional to mirror surface area then a 12" collects 44% more light than a 10". Someone who knows about these things may want to correct me on that. Lightbridge sounds a good way to go to me, but again you'd need a second scope for photography.

One thing I'm sure of, whatever you get you'll have a lot of fun!

Patrick

[Dez]

John, thanks for the offer mate, very kind and I would be very interested in dropping by to check things out first hand.... Only problem is I'm in Canberra this weekend .... I'm guess you're talking about Saturday night?? I'm not back until Tuesday anyway, so just very unfortunate timing... Maybe I might be able to bug you another time!!

Macquarie Uni is having an astronomy night I think 20 Oct with public viewing opportunities supported by members of a local club. I planning on going to this, went about 9 years ago. I remember looking through quite a few different scopes. I'm hoping there are clear skies and plenty of telescopes to help solidify my decision!!!

Gota go, wife is telling me she's hungry....

Chief Cook
Dez

[Gargoyle_Steve (Steve)]

A couple of points come to mind Dez - if you go the Lightbridge path it would make a great observing tool but you can't mount that on any kind of tripod for photography later on. Your only option would be to plant it on a "equatorial table" (do a forum search) which will allow you to line it up on an object and then track for 45 mins or so. Not a bad option, and Mike (the Iceman himself) used one of these contraptions for some time and captured some amazing images this way.

But as others have already said mounting a solid tube 12" on a tracking/tripod mount is one heck of a job anyway, though it can be done it's probably more suitable for a permanent setup and most likely not very transportable, or at least not very comfortable to do so.

Paul's suggestion of something like an ED80 to start you out on imaging, and another scope for observing sounds like a pretty good bit of advice for now. Paul knows a LOT about imaging and you can take what he says on the topic as being gold.


Perhaps another option you could consider would be to buy a 10" (or even 8"?) dob for immediate visual use, and when you're ready to start astro-imaging you can also mount that on an EQ6 (HEQ5 for the 8" maybe?). You can keep the original dob mounting "shoulders" on the main body of the scope AND add rings at the same time for mounting it on a tripod/equatorial head. This would allow you to swap it from it's dob base to tripod mount and back again easily when it suits you. Even an 8" dob is still a LOT of aperture compared to may other scopes used for imaging but it's going to be easier and less expensive to mount on something suitable.

re the $800 difference between a 10" tube body and a 12" truss body dob : I can't say it's not justified, but they are 2 different scopes. A fairer comparison would be the 12" in both body types, which obviously lessens the gap somewhat.

Having said that, if you buy the 10" dob the additional $800 you mentioned is also 4/5's of the way to being able to buy an Argo Navis guide computer plus all the mounting hardware you need to set it up on the dob. This makes for a very powerful combination that will let you find far more objects than you would otherwise, plus it will let you find them far quicker, which means that you spend far more time looking AT something and almost no time looking FOR it.

An Argo Navis is probably of more benefit in your case as an aid to visual observing with the dob, because although the AN can also be used in conjunction with an equatorial (tripod) mount if you buy an EQ6 mount or similar that has full tracking (instead of simply having the motor drives) it will have it's own database of objects that it can automatically find and track - the Argo Navis just happens to have many more objects in it's database and is a far better system!

(If you end up buying the dob and set up the main reflector tube for both dob and tripod mounting as mentioned above you can also swap the same Argo Navis unit across to be used either way. You will most likely need to buy another set of encoders for the tripod mount. Software wise the AN can adapt to both quickly and easily.)

Apologies if this ended up being a bit wordy it originally started out as "A quick point to consider" but I deleted that as more and more things came to mind that I thought may be helpful to you.

[Dez]

Hey Steve

Thanks for the reply and don't apologies for the detail you've included, it is all considered very valuable stuff. I'll definately keep the Argo Narvis in mind too.

I have made a decision re choice of telescope!!! I will be purchasing a 10" GSO dob ...... Either from Bintel or Andrew's Com... I will see who can give the best deal. As for reasons behind my final decision (haven't got it yet, so possibly final!!!):

1) 10" should be enough aperture to intially see a lot and learn a lot from a variety of observing sites, including the backyard.
2) 10" leaves room to upsize to either 12" or 16" sometime soon
3) Price - can't hide the fact the difference of $800 between the 10" GSO and 12" LB has an influence
4) Portability - I'm guessing the 10" GSO will be easier to shuffle around the backyard and traveling to other sites than the 12" LB. I'm also guessing less set up time than the LB truss type too.
5) Inclusions in the package - The GSO comes with 90 deg finder scope and 3 or 4 EP's. The LB comes with the redlight target finder and one EP. While this may be better quality (I'm guessing) only one EP seems a little limiting and I've heard while the red light finderscope is OK, the other regular type is much better. Therefore, I'd need to spend extra to match accessories.
6) If the need arises in the future, the solid tube 10" can be mounted for photography.

While I'd like the extra aperture of the 12" LB, I think I'll be happy with the 10" at this stage and just upgrade if I see the need later. I think a dedicated scope like an ED 80 and suitable mount for astrophotography seems like the go at this stage. As I'm not in the market for this at this time, better to focus on and buy for what I'm planning to use the telescope for now, visual observing, but also keeping in mind ease of use.

Still time to "toss in a spanner" if anyone feels the need!! A week or two should see the deal done...

I will definately post pictures when I get it. So thanks all for the feedback and advice. It has all been greatly appreciated and helped me to make the final decision.

Cheers

Dez

[davewaldo]

Hi Dez

I think a GSO 10" scope is a great decision!

I have one and its been great!

When you decide which store to purchase from don't just look at prices. Some stores offer better service than others.

One thing to check which not many people talk about is centre spotting of the primary mirror. My GSO 10" did not come with a centre spot (which is totaly necessary for collimation). So I would be checking which Suppliers centre spot their scopes. I know Bintel collimate before sending out a scope, so I would assume they would need a spot for this, but I don't know so its worth checking first.

If your scope arrives without a centre spot it is not s nice job to do. If you look in the articles page of this site you will find a how-To for this.

I have done it successfuly but if you are not the hands on, practical type then it might be better to get one with a centre spot.

This is the only thing I can think of to check. Now you have decided on a 10" GSO dob you can't really go wrong in my opinion!

I look forward to reading your "First Light"

Cheers,

Dave.

[norm]

Hi Dez,

Another thing to consider is getting 'Bob's' knob to assist in collimation. Not sure if its a priority, but some people swear by them. Others may comment further.

[xelasnave]

Welcome from me Dez.

When my wife left she blammed it on me buying at 12 inch instead of a new fridge.. disappointing as I felt there were so many other things she could have blamed... I write it off to the old guilt trip and enjoy my 12 inch more than any fridge I have ever owned.

So I live without a fridge and without a wife but still think I spent the money very wisely. Food is for eating not storing for goodness sake.

Good luck with your purchase and be assurred that the dobs available these days are excellent value for the money.
All the best to you.
alex

[Dez]

Dave, thanks for that advice re circle on the primary mirror . I did see the circle on mirrors at Bintel when I was there a couple of weeks ago. I'll definately keep this in mind as a consideration when choosing. I'm usually relatively handy doing things myself, but I think I'd rather have this done than messing around with it myself. I had in mind a laser collimator as a 'must have' to be included in the initial purchase, but didn't know the circle was needed to assist, so thanks heaps for this advice! I have no idea how to use a laser collimator but I'm guessing it should come with instructions, or be obvious when I get it. I'm sure there are posts on IIS re this too. Cheers mate.

Norm, I'm sure there have been a few cracks re 'Bob and his knob', so while tempting, think I'll leave it alone! One question though, does Bob only have one knob? I haven't looked into this too much yet, as you said they assist with ease of collimation, but is collimation still possible with the screws/knobs already there? So is Bob a single knob job, or does Bob come with multiple knobs? Tri-Knob Bob? Either way, another accessory to consider including in the initial deal!

Thanks for the welcome Alex. I've always seen a fridge as an essential too, but that has nothing to do with storing food!!!! Cheers

[davewaldo]

Hi Dez,

Here is a link to an article about collimation of a newtonian: http://www.iceinspace.com.au/index.p...63,390,0,0,1,0

I am happy using a laser collimator, I find it one of the easiest ways to collimate and can be very accurate.

Dave.