Dobsonian vs SCT is there much difference visual observing

[swamp thing]

I think Sumerian Dobs are pretty expensive for what they are...

You are entitled to your opinion of coarse, but I completely disagree. There is a great deal of skilled work involved in these scopes.

As someone that has built scopes I can assure you these are not easy to reproduce. The machine work is both skilled and difficult to do.

Typing that you think they are pretty expensive for what they are without any idea of what work is involved is just totally unfair on the craftsman that builds them.

Let's see you build a few cheaper.

[emadmoussa]

You are entitled to your opinion of coarse, but I completely disagree. There is a great deal of skilled work involved in these scopes.

As someone that has built scopes I can assure you these are not easy to reproduce. The machine work is both skilled and difficult to do.

Typing that you think they are pretty expensive for what they are without any idea of what work is involved is just totally unfair on the craftsman that builds them.

Let's see you build a few cheaper.

Was expecting a response like that I don't by any means underestimate the skill and technique involved, and they are indeed are intricate instruments. But not sure I would pay 4K or more for one...

Having said that, the ability to become very small is impressive. However, not my cup of tea...some find them endearing and very nice, others don't. C'est la vie!

Out of curiosity, Is your 20" home custom built? Looks very nice!

[michael.h.f.wilkinson]

There is a huge difference between a mass-produced Dob and the quality of the Sumerians (or indeed many other higher-end Dobs). Using better mirrors, better materials, and careful design and manufacture produces things which have the same specs as the cheapest ones, but are miles ahead in terms of quality. As an example from another area: I had a Yashica 135mm F/2.8 telephoto lens. Really nice piece of kit, and not too expensive (secondhand for 125 Dutch guilders). Some years later, and no longer a student, I could suddenly afford to buy a Carl Zeiss 135mm F/2.8 telephoto lens, for just shy of 8 times the cost (secondhand as well) of the Yashica. I had a quick look through the viewfinder, and was hooked on the Zeiss lens, so decided to trade in the Yashica (for 125 guilders ). The Zeiss had the same specs on paper, but produced clearly better performance in terms of optical quality, but also in mechanical finish. Was it 8 times better? No, but certainly worth the outlay to me.

[emadmoussa]

There is a huge difference between a mass-produced Dob and the quality of the Sumerians (or indeed many other higher-end Dobs). Using better mirrors, better materials, and careful design and manufacture produces things which have the same specs as the cheapest ones, but are miles ahead in terms of quality. As an example from another area: I had a Yashica 135mm F/2.8 telephoto lens. Really nice piece of kit, and not too expensive (secondhand for 125 Dutch guilders). Some years later, and no longer a student, I could suddenly afford to buy a Carl Zeiss 135mm F/2.8 telephoto lens, for just shy of 8 times the cost (secondhand as well) of the Yashica. I had a quick look through the viewfinder, and was hooked on the Zeiss lens, so decided to trade in the Yashica (for 125 guilders ). The Zeiss had the same specs on paper, but produced clearly better performance in terms of optical quality, but also in mechanical finish. Was it 8 times better? No, but certainly worth the outlay to me.

I noticed with the Sumerians, you've got the options to choose your mirror...some are standard GSO ones,

[jetstream]

This site is great for helping people choose equipment as Alan mentions-the 10" dob recommendation from SGL has been excellent for me.

Emad,Teeters scopes are sure nice eh?!He is also great to talk too and gives prompt replies to inquiries.Teeter also has a unique mirror box truss attachment that looks very good as well

[Daniel-K]

Id certainly pay for the quality they offer, i did infact email and ask them to make me a 18", but they not making anything over 16" ATM BTW staying on topic stick with the DOB!

[emadmoussa]

This site is great for helping people choose equipment as Alan mentions-the 10" dob recommendation from SGL has been excellent for me.

Emad,Teeters scopes are sure nice eh?!He is also great to talk too and gives prompt replies to inquiries.Teeter also has a unique mirror box truss attachment that looks very good as well

Teeters were just an example...I was trying to remember the one I was looking at, which had better specs and slightly cheaper. it was a 20", I think f/3.6 ...

[jetstream]

Yes Teeter is just one of many great dob makers out there-most seem helpful and he is enthusiastic about his craft.Some of these scopes sport wood finishing like fine furniture.Swampthings telescope he built equals or exceeds any of these scopes,all dovetail jointed,great bearings,perfect mirror cell and truss attachment,Steve could build them for a living if he chose

[emadmoussa]

Humm..I didn't know they made them in the UK. How much would you charge for a 20" f/3.5?

Just for future reference..

[jetstream]

In general anyone who is considering a big dob and has questions about prices should first check to see how much the components cost.A top quality 18" primary mirror set will start about 2200 pounds all the way to 5500 pounds,then there is the Starlight focuser,SIPS maybe,mirror cell....oh and the ArgoNavis etc

[estwing]

after seeing it close up its a wonderful scope...

[estwing]

In general anyone who is considering a big dob and has questions about prices should first check to see how much the components cost.A top quality 18" primary mirror set will start about 2200 pounds all the way to 5500 pounds,then there is the Starlight focuser,SIPS maybe,mirror cell....oh and the ArgoNavis etc

haha...oh the money runeth through my fingers!!

[jetstream]

Calvin you also have an awesome scope,that Moonshane makes me envious too,very good craftsmanship.Thanks for the heads up on Nichol optical a while back,his mirrors look fantastic.

To the OP,the choice of SCT vs Dob in bigger apertures like estwings, is clear to me(my opinion) and that is dob.For me having wheel barrow handles on the scope and wheeling half of it out of my truck,then attaching the rest in 21.7 mag skies will be easy and worth it.I know I couldn't do even a 14" SCT under those same conditions by myself.

Lots of good info and things to ponder in this thread

[Moonshane]

I think Sumerian Dobs are pretty expensive for what they are...their EQ platform is reasonably priced though.

If money is not an issue, I would get the 20" version of these... 

try making one, divide the hours by the profit and then tell me you'd work for that!  when I make a dob and sell it, the hourly rate is about £1.20

[emadmoussa]

try making one, divide the hours by the profit and then tell me you'd work for that!  when I make a dob and sell it, the hourly rate is about £1.20

Curious, I've seen an example of your work and it's fantastic...but you still use a 16" OOUK (if I'm not mistaken) for you personally. Have you for instance considered building yourself, say, a 20" Dob?

[Moonshane]

not really. the mass and size of a 20" dob (ignoring the cost of the mirror) are prohibitive to me given my circumstances. I would pretty much have to sell everything I have to buy a mirror of the quality of my 16". I'd sooner have a selection of scopes (16" f4, 12" f4, 6" f11, 6" f5 and 5.25" f5) and eyepieces (a caseful) than one big scope that's likely to be sat unused for longish periods - I use my 12" f4 more than any other scope for night time and my 6" f11 for mainly solar. each to their own though!

furthermore a 20" would be a squeeze though the door, although I know Steve made his to fit his door (or maybe he changed his door, I cannot recall).

all that said, I am part way through a conversion of the 16" to a truss system.

the time taken to make dobs of any quality although enjoyable means I won't be making any more for other people until I retire I think.

[swamp thing]

Yes Teeter is just one of many great dob makers out there-most seem helpful and he is enthusiastic about his craft.Some of these scopes sport wood finishing like fine furniture.Swampthings telescope he built equals or exceeds any of these scopes,all dovetail jointed,great bearings,perfect mirror cell and truss attachment,Steve could build them for a living if he chose

Thank you. That's very kind of you.

[faulksy]

Thank you. That's very kind of you.

myself and dan have both seen steves and calvs (shanes) and they are indeed built by crafts men, the good thing about these scopes is it doesnt matter what the weather is doing, you can either look through them or at them and it makes you feel like you have just climbed the ropes in gym class for the first time

[CodnorPaul]

To the OP - my own experience is my SCT provides a sharper, more detailed view than reflectors which has also been commented on by others who I have been viewing with.  I cant comment on how well collimated the dobs I have looked through are but I know my SCT is well collimated and was well cooled at the time.  The SCT is also a lot easier to handle and I would only upgrade my C8 to a C11.

[AndyWB]

I'm not sure if it helps, but I was curious to compare a C11 and my 250px a few weeks ago. Pointing at Jupiter there was little in it. I felt my 10" had a smidgen more contrast, but the image in the C11 was a smidgen more stable than the 10", even though well cooled. I think a breeze was still causing some kind of current effect in the tube - when it paused the 10" settled nicely.

The main differences I'd expect to be due to the mounts than the optics.

[ollypenrice]

I have a 10 inch SCT, a big Dob and some nice refractors (but I do this for a living.) I probably get the least buzz out of the SCT. I feel hemmed in by the long focal length and just not quite engaged by the view, but that's me, and when I do use it I usually feel it's better than I remember it being! Apart from the field of view, which I do find a constraint.

The OP mentioned imaging. What kind? An SCT is an excellent choice for fast frame solar system imaging but it is a difficult, challenging choice for deep sky. You need a very, very accurate mount, a reducer flattener (probably) and an off axis guider. Everything has to be right before you can approach the quality you'd get straight from a wider field refractor in plug and play mode. I would never advise a new DS imager to get involved with an SCT.

Olly

[Owmuchonomy]

Regarding the original OP, I've had my 9.25 SCT for about 5 years. Yes I'm a humble observer and DSLR imager from Yorkshire. I'm very happy with it but I just bought a 102 triplet. I also try and share my views with friends whenever possible so when they say 'I feel as though I could fall into that cloud' (m42) through the triplet I would tend to agree. But then this spring I just took two photos of Mars and Jupiter with the 9.25 and I must say I'm happy with my efforts. My daughter stepped up to the SCT and saw the Hellas on Mars. Guess what I'm nearly ready to push the button on a secondhand 10" Dob to put in the caravan for camping trips. For me it's all about the chance to share, observe and sometimes photograph the spectacle of our universe. So you won't go wrong with any of your choices. Good luck.

[asset189]

I have a 10 inch SCT, a big Dob and some nice refractors (but I do this for a living.) I probably get the least buzz out of the SCT. I feel hemmed in by the long focal length and just not quite engaged by the view, but that's me, and when I do use it I usually feel it's better than I remember it being! Apart from the field of view, which I do find a constraint.

The OP mentioned imaging. What kind? An SCT is an excellent choice for fast frame solar system imaging but it is a difficult, challenging choice for deep sky. You need a very, very accurate mount, a reducer flattener (probably) and an off axis guider. Everything has to be right before you can approach the quality you'd get straight from a wider field refractor in plug and play mode. I would never advise a new DS imager to get involved with an SCT.

Olly

Olly suppose the question I should have asked is whats a good starter set up for deep sky imaging- any views appreciated  ta

[CodnorPaul]

Olly suppose the question I should have asked is whats a good starter set up for deep sky imaging- any views appreciated  ta

If that's your question then definitely NOT an SCT - an ED80 or GT81 would be a good starting point, or if a reflector then a 200pds.  I love my SCT but it is not a DS imaging scope.  Now you could look at an RC with a reducer for aperture but it depends on budget

[ollypenrice]

Olly suppose the question I should have asked is whats a good starter set up for deep sky imaging- any views appreciated  ta

Well, my advice won't be at all original but I'd say, small apo or semi apo 'ED' refractor on HEQ5 or NEQ6, autoguided. Untypically, perhaps, I'd also advise going straight into monochrome CCD. In the end this is faster and more flexible, opeing up moonlit nights for Ha work. I've said often enough why I believe mono to be faster than one shot colour and given my reasons and evidence so I won't bore you with all that again!

Olly