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David Lukehurst Custom Dobsonian


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Hello all,

I haven't posted in a long while, so although i'm feeling a little guilty about asking for your opinions, I couldn't not seeing as this is going to be a rather serious potential purchase.

so! i've had the 10inch skywatcher dobsonian for almost 3 years now i think. I love it! but... i'm getting a severe case of aperture fever...

I have been looking lovingly at the david lukehurst dobsonians http://www.dobsonians.co.uk/telescopes.html in particular the 18inch ultra portable model.

I'm just wondering if anyone has had any experience with David's custom scopes? how portable are they really? and more importantly how much of an improvement would it be over my 10inch?

It might sound like a daft question but i know that a lot of you play with a range of wonderful scopes. the one I'm looking at is just a little bit less then 4K. Would my money be better invested elsewhere? I love the idea of imaging but seeing everything first hand still wins me over so the lack of GOTO or synscan isn't a deal breaker.

your thoughts and opinions please!

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David's telescopes are very well made and he is a good chap to deal with. He uses the best optics he can obtain so a 18" would be a very noticeable improvement over your 10" on DSO's, planetary improvement has more to do with seeing conditions. Money better spent elsewhere is a matter for debate. :smiley:

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If it has good optics then planetary will improve also. Brightness matters for planets too.

The 18" will be a vast upgrade from the 10" if you're observing from dark skies. The difference will be less obvious (but still present) from more light polluted skies. If you're getting a telescope like this there will be no AP. Even with GoTo you'll be restricted to video astronomy. If you want a killer visual scope then a large Dob is the only way to go. Perhaps you also want to look around at other manufacturers (plenty in Europe). If you Google you should find comments and reviews on David's scopes.

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Hi

TBH I don't see any real advantage to the ultra portable types unless your car is a tiny one. The regular truss style scopes break down easy enough to transport in most vehicles. The ultra portable types can also present problems with using heavy eyepieces, larger optical finders etc.

Shrouding them is also more of a challenge and dew prevention not easy. IMO they are ideal in the desert but on a damp night over here not ideal.

I would opt for a one of his regular truss scopes myself. He has a good reputation for building some fine scopes.

Personally I would keep your 10" scope too as this makes a great second scope to a big un. The 10" proving "just right" for when conditions make hauling the big scope out unfavourable.

Visual is my thing. Using a big scope at a dark sky site is the ultimate visual treat and IMO it doesn't get any better than that.

You could try getting one of the budget (Skywatcher or Meade) 16" scopes and see if large scopes are your thing. This is what I did. I bought a budget one first to see if it was something I wanted to do. After owning a 16" scope for a few years and thoroughly enjoying every moment of it, I decided to build my "scope for life". This way, if, after a few months you think this is not where you wanna be, you can sell the budget scopes at no great loss, specially if you bought it second hand.

If on the other hand you love it you can then get your ultimate scope. The real jump here is quality though not aperture. Moving from a budget scope to a premium one.

The jump from 10" to 16" is a big one. Objects are considerably brighter through the big scope. You can really see detail in a few Galaxies and the number available to observe jumps dramatically. Diffuse nebulae really are impressive with an O-III you can get astonishing detail from dark sky sites with some like the veil nebula giving black n white photographic views. Globula clusters are often resolved right to the very core. The brighter ones are way better than any image shows them. I find open clusters better in smaller scopes myself as the FOV in larger scopes starts to get a bit restrictive. Planets can be breathtaking, if the seeing ever steadies enough a big scope can give unbelievable planetary views, but trust me this is rare in this country. Often masked down gives the best views ( these can still be stunning though and rival the best mid sized fracs I've looked through) .

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A killer visual scope is what I'm aiming for. What kind of sights should I expect? how much detail could be seen on DSO's? dust trails on and a spiral shape on the whirlpool for example? or is more aperture still required? My current eyepiece set would ae

As for the other manufacturers, can you name any that you would recommend? I was looking at the US obsession, but delivery costs would nip that in the bud.

Many thanks guys,

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Thanks for that Steve, very informative. I like the look of the build quality and mirror quality with David's custom work. The reason the ultra compact seem desirable is that my car isn't that big. its a ford focus! the 10inch fits nicely (solid tube) but the way the ultra compact scopes disassemble looks very appealing. I would probably keep the 10 too.

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I've seen regular 18" Obsession fit into a 4-door non-hatchback. The guy had to take the mirror out, though. I echo Steve's point about ultra-portable. This sort of scope can well be a lifetime purchase and you want to get it right. Consider whether you want to sell the car and get a hatchback and go for a traditional truss Dob. I know that sounds radical, but it should be something you at least consider, IMHO. You'll probably be keeping the scope longer than you keep the car. I would recommend you buy David Kriege's book (from the Obsession site). It's really worth reading (even if it's a bit out of date now and some things aren't accurate). It gives the history of large Dobs and what you want to look for when building or buying. Even if you don't build (which you're not doing), it's worth a read.

You will see detail in M51, yes. You'll see the spiral arms. You'll see HII regions in M101 very clearly. Multiple HII regions in M33. The planetary nebula in M15. The Veil will look photographic from a dark site with an OIII filter. You will see all of it, even the fainter inner regions. The larger DSOs affect your night vision from a dark site.

Another thing I would do is to investigate the optical companies. David (should you choose to go with him) will put any mirror into your scope. Not all premium optical companies produce premium optics all the time. Do your research. Read up on what other people recommend. Look in Europe and in the US. It may be financially reasonable to import a mirror from the US, should you want to go that route. People have been stung with bad (and do mean bad--real dogs) mirrors in the past from premium optical houses. So choose your supplier with your eyes open. Don't just go with one because your builder recommends them. I don't know who Lukehurst recommends, BTW, I'm just urging you to do your own research. Ask on this forum. Ask on Cloudy Nights. Google it: there's a German guy who's tested loads of mirrors and keeps getting legal threats when he posts results so he must be doing something right.

Finally, if you want other builders of low-profile Dobs you could look at: www.sumerianoptics.com/en There's also a guy in Germany whose name I've forgotten. There'll be others too, I just don't know them. Ask around.

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.....A killer visual scope is what I'm aiming for. What kind of sights should I expect? how much detail could be seen on DSO's? dust trails on and a spiral shape on the whirlpool for example? or is more aperture still required? ....

I've viewed through a 20" David Lukehurst dobsonian and the views were simply amazing. M13 was a huge mass of stars, resolved to the core and filling the field of view. M51 showed it's glorious spiral structure and many clumps and tonal variations within the spiral arms. The "bridge" across to NGC 5195 was striking and showed structure and texture.

These views were at a decently dark sky sight and will live with me for years :smiley:

Scopes like this need / deserve good eyepieces as they are usually pretty fast (the 20" was an F/4 I believe) but they really do open up the universe visually.

My 10" Orion Optics seemed rather humble for a while after the above experience :rolleyes2:

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It just happens that one of our club members having obtained a 16" quality mirror gave the job of turning it into a truss Dob scope to DL, and a splendid job he made of it, can be assembled in minutes and very transportable, and the views, especially through an Ethos are just excellent. Not my cup of tea though, I have problems standing on steps at night, I tend to fall off :eek:

John.

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I have a 16" f4 dob with a solid tube and it fits in my Rover 214i hatchback. I may eventually make a truss version of it but it's not essential. also, I have a 10" ultra portable to try to make first. the increase in image brightness compared with my old 12" is amazing, even in light polluted skies where I live. I am pretty lazy and don't get out that often - also have family commitments, but when I do - wow.

you'll never regret the right aperture for you but even at 6' 3" I wanted to ensure I had a scope I could use on the ground at all times. I think I am happy with my scope and even a 16" f5 would mean ladders I think or a step and that would wind me up eventually.

everything is better in my opinion with this scope. I routinely mask the aperture for bright objects and the view is often far better given the seeing.

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Thanks all. I will definitely do my research into mirrors, and maybe try and contact that reviewer, as you said if he's being threatened with legal action he must doing something right. I would pick up some new ep's along with it, probably from the televue range. Might have to investigate an ep calculator.

As for changing car, this could very well be on the cards but by the sounds of things even the regular dobs from David would fit. Brantuk, thanks for the link I will investigate that too.

This is all very exciting!

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