Thinking about getting a biggish Dob...

[Andymarrison]

Hello all

After a bit of a break due to new job, moving house etc, I've managed to get the tackle out again and put in some observing hours, which I'm really enjoying. The new place is in a pretty dark spot, and last night I found myself wondering what all those lovely Messiers would look like in a bigger scope...a common affliction, I believe!

Given that I have limited set-up and observing time, I think I've settled on a 14" push-to Dob - 14" because it should be a meaningful step up from my 8" Celestron, should still just about be one-man portable (I think I'd struggle with the extra weight of the full goto solution), and I hopefully won't need a stepladder to observe at zenith. The scope will be stored in a shed which I don't think will take a fully set-up tube and base, so I'll need something that I can take apart and assemble again before observing.

At the moment I'm trying to decide whether to get a 350p skyliner flextube, and then retrofit the nexus push-to system (encoders, serial to wifi unit), or whether to go for the Orion 14" intelliscope, which I believe has the same optics as the skywatcher but comes ready with the encoders etc installed. Not sure if there's any real difference between the two - if not then I guess the Orion is the obvious choice since I won't need to use my dubious DIY skills!

Any views?

[NGC 1502]

Are you able to get to a dealer with showroom stock ? You can then directly check eyepiece height at the zenith, weight of the components / mount, how easy to assemble and take apart, general workmanship etc.

Good luck with your choice, Ed.

[todd8137]

Hi there big dobs are great if you have the room, ease of set up, some stable for you stand on,dark skies ,then big dobs are great they are a handful ,but the view at he ep make up for most of that.they weight a bit so. A good back is needed ,of obsy get the highest one the pocket can aford and keep in mind how heavy they can be good luck with your voice

Pat

[umadog]

I used to have a 12" Inteliscope and really liked it. Optics are gamble from any manufacturer, but all the Orions I've looked through have always been good. If you keep it in the garage you can easily wheel it out if you make a suitable contraption for the job. My only beef with the XX14 is that it's particularly heavy. The XX12 is pretty manageable at 85 lbs, but the XX14 is a whopping 120 lbs. It's worth keeping in mind. Also, in case you're concerned, a 12" will provide a meaningful improvement over an 8".

[Andymarrison]

Thanks chaps - yes, I was just looking at the weight of these things and you're dead right that, given the limited time I have to observe, anything that's too heavy is just going to put me off getting the thing set up. So I think a 12" is indeed probably the way to go. I'm now thinking about getting one from David Lukehurst with the nexus encoders etc fitted, although that will take me a while longer to save up for...thanks for the advice!

[umadog]

No problem at all. Whilst I agree that the 12" may well be the way to go in this case, let me give you a little food for thought. If you're keeping the scope in a garage and just wheeling it outside to observe then the weight is largely irrelevant. What matters more is how fast your mirror will cool. If your garage is unheated, then you're likely onto a winner here regardless of the mirror thickness. If you have to wait for the mirror to cool, then a thinner mirror provides major benefits. However, you at this point reach the domain of non-mass-produced scopes. The other thing that matters is how easy the instrument is to set up. If, after wheeling out, you still have a lot of cables to mess around with, etc, then this will increase your set up time. So remember to look at the whole picture and not just the weight.

[Andymarrison]

Thanks umadog. I've been thinking about what I'd really like out of the next scope, and where it's going to be kept and used as you suggested. It'll be in an unheated "log cabin" right next to the deck I'll be using for observing, so I should have few problems either with cool down time or with wheeling the scope out (I've just caught on to the idea of wheelbarrow handles for large dobs, and they look like they'll be just the ticket for moving the thing from cabin to deck). Very occasionally I might want to put the scope in the car to head off to a properly dark site, but it's a big car and I don't think that should be a problem. So really it probably comes down to aperture and observing height at zenith. I also think this will be my "once in a lifetime" scope, so I want to get the best I can afford. With all of this in mind I'm currently thinking about either a 14" (f5) or a 16" (f4.4) 1/10 wave David Lukehurst Dob. I've got a few green and black EPs so the fast f-ratio hopefully won't be an issue with those. Time to start saving....!

[umadog]

At below f/5 you'll likely also want a Paracorr.

[Paul73]

If weight of a full GoTo is an issue. Why not ditch the electronics and do it manually?

Could be that from your new location you can see enough for easy star hopping (but not so many as to confuse things)!

Paul

[Mr Spock]

If you are keeping it in a shed, is the shed door wide enough to get the base unit out? You may find that is thing which limits the size of most people's Dobs.

[Andymarrison]

It's a double door, so should be no problem there. I'd thought about a purely manual solution, but to be brutally honest I'm just too lazy and get frustrated too easily to learn any serious star-hopping! I've got used to Sky Safari on the iPad with my CpC 800, hooked up through a serial to wifi box, so wanted to keep that functionality for the new push-to scope - hence thinking about the nexus system, which seems to have a good reputation? And thanks for the Paracorr tip umadog (quietly adjusts budget without wife noticing to include more Televue kit!)

[Scooot]

Andy, have a look at these, I have a 16" Canopus on order. Eyepiece height is 162cm for the f4.5 and the recent scopes are lighter than the older ones. The nexus set up weighs hardly anything and he'll fit encoder arms in the build.

http://www.sumerianoptics.com/en/

[Andymarrison]

Andy, have a look at these, I have a 16" Canopus on order. Eyepiece height is 162cm for the f4.5 and the recent scopes are lighter than the older ones. The nexus set up weighs hardly anything and he'll fit encoder arms in the build.http://www.sumerianoptics.com/en/

Yes...they do look very, very nice! I quite like the look of the Alkaid, as well. The only think that put me off a little bit was how exposed the primary mirror is, although I guess a shroud would cure that pretty quickly. Out of interest, Scooot, what made you go for a Sumerian as opposed to another premium Dob manufacturer, and why the Canopus over the Alkaid? If I can understand your thought process it might help me make up my mind what to do!

[Paul73]

Andy, have a look at these, I have a 16" Canopus on order. Eyepiece height is 162cm for the f4.5 and the recent scopes are lighter than the older ones. The nexus set up weighs hardly anything and he'll fit encoder arms in the build.

http://www.sumerianoptics.com/en/

i

There goes your budget........

[Scooot]

Andy, have a look at these, I have a 16" Canopus on order. Eyepiece height is 162cm for the f4.5 and the recent scopes are lighter than the older ones. The nexus set up weighs hardly anything and he'll fit encoder arms in the build.

http://www.sumerianoptics.com/en/

As a step up from my 10" I wanted no less than 16" if I could avoid a ladder. At this size I wanted to avoid a solid tube even though I love my OO scope. I had thought I'd need an f4 so when I found out the f4.5 was OK without the ladder it made it more attractive. I thought the secondary on the Canopus was more protected than the Alkaid even though they come with dew heaters and I will get a shroud. Their compactness, and I thought they were very light for the size, together with a design which I liked was very compelling. Although any 16" is large I wanted to make ease of set up and manoeuvrability the best it could be without compromising stability or other important functions too much. I wanted good optics and I know OO's are excellent but I'm sure they'd fit other makes if I'd wanted. I'd read and had good reports about them and pricewise the exchange rate is quite good, but obviously dearer than off the shelf manufacturers. I wouldn't have considered anything to which I couldn't fit my Nexus and encoders because its revolutionised my viewing experience. So the fact they'll fit the encoder arms as part of the process was also very important to me.

I suppose in the end it was between these and Mr Lukehurst's and I chose these. Hopefully it'll turn out to be a good choice, good luck with yours.

Whoops sorry, wrong Quote Andy : -)

[Mr Spock]

A big Dob with tracking is very appealing. I might have gone that route had I not already commited funds down the current path.

[Scooot]

A big Dob with tracking is very appealing. I might have gone that route had I not already commited funds down the current path.

There's no tracking with the Nexus push to if you were thinking of this, don't know about the intelliscopes. -

[Andymarrison]

...i think you've convinced me Richard - the Sumerians look a fair bit lighter and as you say the exchange rate makes them pretty attractive at the moment (once I "hedge" my sterling-euro exchange rate risk!). They look beautiful, too! Which OO mirror did you go for - 1:6 1:8 or 1:10?

[Scooot]

...i think you've convinced me Richard - the Sumerians look a fair bit lighter and as you say the exchange rate makes them pretty attractive at the moment (once I "hedge" my sterling-euro exchange rate risk!). They look beautiful, too! Which OO mirror did you go for - 1:6 1:8 or 1:10?

Well after canvassing everyone on here it became clear that perhaps I didn't really need the best optics with a 16".

http://stargazerslounge.com/topic/223685-big-dobs-planets/

I eventually got it so to speak when someone explained its a bit like looking through a honeycomb, and with a large aperture getting good seeing through enough of the honeycomb windows in the UK to take advantage of the optics is very rare. Having said that I went for an OO 1/10PV because it wasn't much more relatively than an 1/8 and I just didn't fancy trying the 1/6PV. In for a penny.....

Btw I'm not trying to convince you, just showing the option, I have no first hand experience of them and know only what I've read and heard. Fingers crossed... -

[Andymarrison]

There's no tracking with the Nexus push to if you were thinking of this, don't know about the intelliscopes. -

No, I reckon I can cope with manual tracking, so Nexus should be fine. Manual finding is another matter, however!

[Daniel-K]

forget the 14 and go straight to a 16" that will keep Aperture fever at bay a 14" wont!

[Andymarrison]

Well after canvassing everyone on here it became clear that perhaps I didn't really need the best optics with a 16".http://stargazerslounge.com/topic/223685-big-dobs-planets/ I eventually got it so to speak when someone explained its a bit like looking through a honeycomb, and with a large aperture getting good seeing through enough of the honeycomb windows in the UK to take advantage of the optics is very rare. Having said that I went for an OO 1/10PV because it wasn't much more relatively than an 1/8 and I just didn't fancy trying the 1/6PV. In for a penny..... Btw I'm not trying to convince you, just showing the option, I have no first hand experience of them and know only what I've read and heard. Fingers crossed... -

...and I appreciate you all sharing your experiences - I know you weren't trying to do a selling job, Richard, "being convinced" was just a figure of speech - no offence intended if indeed any was taken!

I feel like you regarding the optics by the way - for the price of the scope, the difference in price moving from 1/6 to 1/10 makes the 1/10 seem like the one to go for. When does yours arrive?

[Andymarrison]

forget the 14 and go straight to a 16" that will keep Aperture fever at bay a 14" wont!

Yes, I think I will! It's a once in a lifetime thing, after all, and now I know that I won't need a ladder there's nothing stopping me (apart from the small matter of finding £3k, of course!)

[Scooot]

...and I appreciate you all sharing your experiences - I know you weren't trying to do a selling job, Richard, "being convinced" was just a figure of speech - no offence intended if indeed any was taken!

I feel like you regarding the optics by the way - for the price of the scope, the difference in price moving from 1/6 to 1/10 makes the 1/10 seem like the one to go for. When does yours arrive?

No, no offence of course. Its just easy to get carried away with my own views which might not be appropriate for others.

They said 8 weeks, which is up early November but haven't heard any more since.

Also for info, since I ordered it I've heard that OO are working on a truss Dob. I've no details of timing or anything else.

[Daniel-K]

Yes, I think I will! It's a once in a lifetime thing, after all, and now I know that I won't need a ladder there's nothing stopping me (apart from the small matter of finding £3k, of course!)

doesnt have to be 3K. i picked up an excellent 16" mirror on ABS for £400. if you want more information just pm me