Hi, well was considering buying a 12" dob early next year but thought I might as well sp3nd a bit more and go the whole hog so am looking at a 16"meade lightbridge...spoke to the guy at Bintel in Sydney who answered a few concerns I had: does anyone have one and could you give me any advice - I currently am using an 8" dob.....thanks!
Hi Shaun , you are really going whole hog , aint ya ? '
I have friends with both the Bintel 16 inch lightbridge and GSO 16 inch truss tube from Andrews Communinations .
Optically they are both AWSOME!!! , you cant beat aperture , but they are both BIG!!! , and I mean BIG , huge scopes , but well designed and quite user friendly if you are strong and good with your hands .
They take about 20-30 minitues to set up on the field and its on the dark field that these big boys perform , very well . (motling detail on NGC 253 was easily seen from the suburbs of Perth saturday night in the LB 16 inch and 17mm Delos , nice )
Ok , so now the LB from Bintel is $2200 with one 26mm eyepiece (2 inch)
and the GSO from Andrews is $1999 with 5 eyepieces , 35mm ( 2 inch ) 25 , 15 , 9 and 6mm ( 1 1/4 inch ).
Your choice Shaun , both are very good , but be prepaired to fine tune both to suit your tastes , its mandatory (and lots of fun) with these , others will pipe in here and I am sure the advice will be good , as always .
Good luck , either way you wont be dissapointed .
Brian.
I have the 16" GSO and it is a very good scope for the price. I built a new base/mount for it out of marine ply because the stock one was so heavy, this makes it easier to move around. Using the old wheel barrow handle trick I can move it from the shed to any spot in the yard easily. It also breaks down into three pieces for transport, so in some ways it's easier than my 12" tube dob to move in a vehicle. I looked at the Lightbridge as well as the GSO but the price favours the later, and the GSO ALt bearing is a much better design than the old style Lightbridge. Some will argue that the lightbridge cross strut style is stiffer than the box strut design of the GSO but they both have drawbacks and can show flex at various altitudes. Collimation at 45 degrees is a good idea. BTW with these two collapsible dobs you will need to collimate every time you take it apart and put it back together.
Thanks guys, very valuable advice! I suppose the 16" is also good for planetary viewing?
The 16" will give you a bright image because it's working from a large aperture. But good planetary viewing is about seeing surface detail which requires good optics that can resolve the detail.
At the very least the LB will provide nice planetary views, and if you score a good mirror the viewing will likely be very good. But the mirrors are a little more variable in the mass produced telescopes.
Where telescopes like this excel is deep sky. If you are looking for a really good planetary telescope there are other options.
Thanks again! I have a feeling that a 16" scope would provide pretty darn good views of planets compared to an 8" scope...! I realise refractors are the go for planetary viewing (or maybe photography mainly): but large aperture should make for great viewing!
Shaun looking at jupiter with a 16 inch will make you blind in that eye , so bright you will loose dark adaption so you are better off making an 'off axis aperature mask' about 6 inches in diameter , giving about a 6 inch f12 un-obstructed telescope , now you are talking !!!.
The luna/planetary views thru that would be awsome ! .
Thats the 1800mm fl of the 16 inch divided by the 150mm aperature mask's diameter , thats 12 so it will be f12 .
Brian.
Quote:
Originally Posted by PSALM19.1
Thanks guys, very valuable advice! I suppose the 16" is also good for planetary viewing?
Hi Shaun, I have a 16" Lightbridge which I purchased when Meade was running a special deal on them some time ago. Despite being promoted as a large aperture portable instrument, I believe they are not. From memory the all up weight is around 72kg, so the only way I found it could be moved was by making a flat plywood trolley fitted with some good castors. I used this to shift it outdoors. Don't forget you still have to unload it off the trolley before use. My scope is now permanently installed on an equatorial mount. The only mechanical design issue I found was at lower altitudes there is quite a deal of movement where the trusses attach into the sockets on the upper & lower optic tubes. I overcame this by drilling and tapping some small holes and fitting some s/steel grub screws. Obviously this is not an option for you if you plan to keep it as a transportable instrument. There is a deal of coma evident in the FOV, but for my application this does not concern me. I believe this could be alleviated by using a commercially available coma corrector. For the price they really are a lot of bang for your buck!
Shaun,
here is a photo of my setup to which shows this is a relatively straightforward conversion. For some reason this did not upload on my previous post.
Graeme.
Wow! I'm licking my lips at that photo Graeme! And how do you find planetary viewing? Am I better off with a 12" perhaps? Astro photography isn't my bent so Dobs all the way for me! A 12" inch is cheaper, but not really by a whole lot. I have a few months of decision making I guess: oh and, would a filter cut down some of Jupiter's brightness? Thanks again for your time guys!
Got your eyes on good buddy ? ,,,
An off axis mask will do it as I say .(google it)
But yes that set up of Graeme's is a beaut no doubt there .
Brian.
Quote:
Originally Posted by PSALM19.1
Wow! I'm licking my lips at that photo Graeme! And how do you find planetary viewing? Am I better off with a 12" perhaps? Astro photography isn't my bent so Dobs all the way for me! A 12" inch is cheaper, but not really by a whole lot. I have a few months of decision making I guess: oh and, would a filter cut down some of Jupiter's brightness? Thanks again for your time guys!
Since I have both the 12" and the 16" dob, I think I can say the 12" will get used more. There is a saying 'the best scope is the one that gets used the most'. As the 12" is essier to move as a single unit, weighs less, and has a smaller foot print it will get used more probably.
I really do appreciate the advice everyone! It's alot of bucks to spend, so I'd be wanting to make an educated decision! Here's the low down put simply:
1. A 12" scope would cost less so I would be able to buy it sooner
2. If I had a 16" it would stay set up the majority of the time in my garage and be moved about 5m from where it sits; I have a flat trolley that I currently use for my 8"; I'd say that with a bit of "jimmy-ing" I could move a bigger scope with it
3. When I look through an 8" at Jupter, I see a little detail (mind you, I've only ever looked when its low to the horizon and Spring is not necessarily a great "seeing" season); so how much more detail is a 12" going to show me? I do like looking at DSO as well but really prefer Lunar and Planetary (but not photography at this stage!)
4. Thanks Brian for info on the "off axis mask"; did google it, but opinion seems to be divided on the subject!
5. Getting a 12" may free me up to buy some grander eyepieces!
So there you have it! Aren't you glad you're not me!
There is also a big difference in the mass of the 12" and 16" mirror - and as it is not low expansion glass ( similar to plate glass ) you will get better images for lunar and planetary with the 12" which will be closer to seeing limited on good nights ( assuming you have good optics in the first place ) .
An aperture stop will give a superficially more stable `sharp' image on poor nights but you will always see just as much without a stop as with one ( assuming again that the edge zones of the mirror are good )
3. When I look through an 8" at Jupter, I see a little detail (mind you, I've only ever looked when its low to the horizon and Spring is not necessarily a great "seeing" season); so how much more detail is a 12" going to show me? I do like looking at DSO as well but really prefer Lunar and Planetary (but not photography at this stage!)
5. Getting a 12" may free me up to buy some grander eyepieces!
So there you have it! Aren't you glad you're not me!
When the seeing is good to very good, my 12" SW Dob delivers the goods. I can easily make out the shadows as its larger Moons transit and that is through humble EP's. When the seeing is good and I get to borrow a Pentax or TV EP I need to be dragged away from the scope. I take the time to ensure collimation is spot on, so this helps a lot. I have looked through a few big dobs to compare and they are sometimes let down by not being aligned with care.
Sometimes I start thinking about a bigger scope but that is quickly cured when I have helped others pack up their gear. The 12" SW Dob is as much as I am willing to move around at the moment.
I don't have either a 12" or 16" dob, but two other members of the club (Western Sydney Amateur Astronomy Group) do have 12" dobs. One has a Meade Lightbridge 12", one has a Skywatcher 12" Goto. I was interested in either a Orion 12" goto dob or the massive 16" got dob.
The gentleman with the Skywatcher said it was as heavy as he ever wanted to cart around. He said that any bigger would not get used. Just too cumbersome, too heavy, and you need a stepladder to get to the eyepiece at zenith targets.
The gentleman with the Meade said it was a good scope for him (no goto, very light, easy to setup and pack). He did not want to go any bigger either.
The club has access to a 30" dob (yes, 750mm of goodness), and we have looked at Jupiter and Saturn (and lots of other stuff too). While it **is** bright, the view is really astounding.
I think that for astounding improvements, the jump has to be something like this - from 12" to 30" or thereabouts. The difference between a view in the 12" and a view in the 16" will not be astounding. It will be a bit brighter, a bit better (depending on local factors) but it will not be astoundingly better.
So I would suggest that you might wish to drop in with a 12" dob rather than the 16", and save your pennies for a Massive Scope later on.
As always, feel free to take any advice as you wish.
Thanks again all: some really helpful advice! Emailed a guy from SDM Telescopes (if you want to dream a bit, check out their massive Dobs! Oh and massive price tag!) He suggested a 14" Skywatcher Dob from Andrews; he believes the optics in this scope are the best commercially available...might be worth a look although the price is up around $2500...more thinking! Thanks again all!
Just a note there on portability . The base of the Skywatcher 14" will not go through a standard door.
Mass produced optics are always a case of buyer beware....lemons will still get out. I encountered an Orion 8" dob ( GSO Optics ) the other week with a mirror that was so bad , no appearance of clear focus could be attained even with a 30mm eyepiece and medium and high were unusable. The owners were oblivious of the problem . This level of problem I'm sure is rare but it does happen.
Hi Shaun, I thought about the 12 and ended up with the 16, so I understand where you’re coming from! I have the 16" LB, and it is a real pleasure to play with. Optics, as far as I can tell on mine, are excellent - I've had favourable comments from those with more expensive optics, but maybe I was just lucky with this mass-produced mirror. The views on good seeing nights of Saturn were absolutely mind-blowingly crisp and colourful, and being able to look at the Neptune-Triton pair with Neptune as a tiny blue disk was also memorable. It is for deep sky objects that the large aperture really performs - you can see and resolve many more star clusters in the Magellanic Clouds, see a ridiculous number of galaxies on a good night (so chart-wise I needed to upgrade from SkyAtlas to Uranometria), and see details where you never imagined in all sorts of objects. I recall panning from NGC346 in the SMC and finding a clearly-resolved small cluster, happy I'd probably hit NGC330, which was similarly resolved in an 8" scope. Except I then panned a bit further and actually found NGC330, much larger, brighter and bursting with stars ... way more impressive than I'd imagined! There is no way you’ll run out of things to look at with a scope of this size.
But, as mentioned before by others, there are downsides:
1: The sheer size and weight of the scope is an issue, and portability is dependent upon your physical fitness/strength. I have a lifting shoulder strap looped around the altitude bearings to help move the assembled OTA from house to garden, but it is not a trivial task to move the scope around, especially for those who have a bad back etc. Even the lower part of the OTA is a sizeable weight. If you have the means to apply mods like 'wheelbarrow' wheels and a storage location that is on a level with your observing location, it will help a lot. I would imagine the 12” is much more portable as it’s a lot lighter.
2: The base mounting unit can be a tight fit for some doors if carrying it outside due to the large diameter of the base discs - usually I either carry it sideways or roll it through doorways, but this may be putting a lot of strain on the small azimuth bolt. I intend to build a new smaller/lighter base unit at some stage to resolve some of these issues a bit like Glen describes above.
3: If you have a small car this scope will do a good job of filling it. That said, the base unit does fit onto the back seat of most 5-door small cars, alongside the lower part of the OTA. For such a big scope it is remarkably transportable in a modest car, but only if you plan on taking not much more than your wife and camping gear to the dark sky site!
4: The aperture is very unforgiving on cheap eyepieces. It comes with a Meade 26mm wide angle eyepiece, which give fun views but the field curvature/coma is pretty bad. I now have forked out on one premium eyepiece (14mm Delos), and it hardly leaves the eyepiece barrel now (or gets paired with my Barlow), as the views are so much better than those from my old Plossls - much flatter and crisper to the edges of the field. With an 8" scope, I never had such issues, but I’d recommend factoring a premium eyepiece into your budget considerations.
5: As others have mentioned, collimation is critical - I have the Orion laser collimator to help, and would definitely recommend a collimation aid of some sort. Performance also noticeably improves on a spell of use of the mirror cooling fan.
Would I go back to the smaller aperture even with these issues - nope! The views are utterly awesome on a good night and well worth the extra time and effort you need to put in on collimation and mirror equilibration time, and the inconvenience of moving around a big scope. But it depends on your situation…
. (motling detail on NGC 253 was easily seen from the suburbs of Perth saturday night in the LB 16 inch and 17mm Delos , nice ) 
.
Shaun looking at jupiter with a 16 inch will make you blind in that eye , so bright you will loose dark adaption so you are better off making an 'off axis aperature mask' about 6 inches in diameter , giving about a 6 inch f12 un-obstructed telescope , now you are talking !!!
Got your eyes on good buddy ? ,,,
