Revelation 16inch Dobsonian

[Astronolee]

Don't underestimate the importance of image scale. This is the prime reason for using a telescope in the first place.

All extended objects in the night sky are at their maximum surface brightness when viewed with ones naked eye alone. Their surface brightness can never increase regardless of what size scope you use. All you can increase is image scale. This is how the telescope works it makes small objects bigger. The bigger an object, the better we see if.

The difference in image scale at each exit pupil between an 8" and a 16" is huge. The 16" will offer an image twice the size of your 8" for each exit pupil. This is a massive difference.

From urban LP locations this difference is less pronounced as most fine detail is hidden by LP anyway, but get out under dark skies where a 16" can stretch its legs..........I'm afraid your 8" is eating dust my friend.

The darker the skies the further ahead the bigger scope pulls. I never missed my 16" after I sold it when using my 10" from LP locations. From dark skies it was another matter I was climbing the walls with aperture fever.

So the revelation 16 inch under darker skys seems preferable regardless of mechanics/quality etc...This was my initial thought...Great advice so far guys thanks :-)

[swamp thing]

So the revelation 16 inch under darker skys seems preferable regardless of mechanics/quality etc...This was my initial thought...Great advice so far guys thanks :-)

It has to work. The mechanics need to work else you won't be observing anything, hence my first post. The post you've quoted is in response to what a 16" can show you, but it needs to work.

[ollypenrice]

I have a twenty inch Dob which I bought from the 'first time Dob builder' who built it. I paid £1400 for it ten years ago. It has been an excellent buy and is widely enjoyed by all who use it, though it does not have premium optics. I'd make the following points;

Scaling up the cheap particle board construction used satisfactorily on the smaller cheap Dobs might not be a good long term bet. I don't know how this particular scope is made and haven't see one.

Moving it at all does not appeal to me. Sir Isaac, as we call him, spends his days reclining under a roll off shed, or maybe 'box' would be a better term. It is no bigger than it needs to be. He is up and running in sixty seconds. This is great and is what I'd recommend to anyone considering a big Dob.

The wheelbarrow handles are questionable for an assembled scope. There is no issue in using them to move the primary components but using them with the truss and secondary in situ might be quite risky. Assembling the top each night would not appeal either.

On the faint fuzzies the aperture is fabulous. While I understand the theory of it not being possible to increase surface brightness, I find this a misleading way to describe the subjective experience of  obseving at large aperture. Subjectively (I stress this) I feel that a big scope does make faint things brighter.

A big Dob would never be my choice for the planets. I prefer a higher azimuth bearing, premium optics of smaller aperture and tracking.

Olly

[estwing]

I nearly bought every 16" that came up on abs.. Then was pointed in the right direction by someone with experience of big dobs and whole hoo har of transport and so on...I was a very lucky man,as they say you only cry once when buying quality

[spaceboy]

Whatever you do decide on Astronolee I would recommend you signing up to the Telescope house news letter and waiting till after the August bank holiday just in case TH offer a 10% off voucher.

From what I have observed over the years is that people often throw caution into the wind when they think they are getting a really good deal. You have to at the end of the day be a little dubious about mirror and build quality for what they are offering this scope at but you also got to think these can be improved on over time albeit at greater expense. 

I'm aware from previously read reviews that Meade, Revelation, GSO mirror coatings are not as durable as on SW mirrors and that the primary springs need upgrading almost immediately to hold better collimation so this is something to also take into account.

[Paul73]

So how dark does your sky need to be to warrant one of these magnificent beasts??

Paul

Astronolee - hope that this question is OK on your thread as I am going through a similar dilemma (although it is from a future proofing my, soon to be built, "Dob Hutch" angle).

[quaoar]

This picture I took recently was with my iphone. You can imagine how good the view really was. It was in my light polluted back yard with my 18" Plettstone scope  /  Zambuto mirror that I wheeled out my backdoor. You cannot beat a quality mirror on a quality scope. I bought this scope secondhand.

The cheap big dobs in this range are a letdown, the bases are unergonomic chipboard rubbish and too heavy, the mirrors are poorly figured and mirror makers don't like refiguring them because the glass type has strains, the secondarys are cheap, poorly figured and nasty, the Alt bearings are way undersized, the focusers are coarse and sloppy, the design actually means the scope is poorly balanced, the mirrors are usually silastic glued to the mirror cell and induce astigmatism.

I personally think the manufacturers are letting the hobby down by cutting corners too much on these scopes. Most of the issues I've listed could be addressed by the manufacturers at a price point about double the current 1299. Sorry I hate to be a wet blanket but these scopes are a compromise layered on top of another compromise.

[Scooot]

This picture I took recently was with my iphone. You can imagine how good the view really was. It was in my light polluted back yard with my 18" Plettstone scope  /  Zambuto mirror that I wheeled out my backdoor. You cannot beat a quality mirror on a quality scope. I bought this scope secondhand.

The cheap big dobs in this range are a letdown, the bases are unergonomic chipboard rubbish and too heavy, the mirrors are poorly figured and mirror makers don't like refiguring them because the glass type has strains, the secondarys are cheap, poorly figured and nasty, the Alt bearings are way undersized, the focusers are coarse and sloppy, the design actually means the scope is poorly balanced, the mirrors are usually silastic glued to the mirror cell and induce astigmatism.

I personally think the manufacturers are letting the hobby down by cutting corners too much on these scopes. Most of the issues I've listed could be addressed by the manufacturers at a price point about double the current 1299. Sorry I hate to be a wet blanket but these scopes are a compromise layered on top of another compromise.

I saw you mentioned the Astrosystems telekits in an earlier post. Would you consider these to be quality scopes or is the quality fairly dependent on the DIY skills of the buyer. I realise the optics are down to the buyer. I am quite taken by this idea but my DIY skills are not as good as most peoples.

[Astronolee]

This picture I took recently was with my iphone. You can imagine how good the view really was. It was in my light polluted back yard with my 18" Plettstone scope / Zambuto mirror that I wheeled out my backdoor. You cannot beat a quality mirror on a quality scope. I bought this scope secondhand.

The cheap big dobs in this range are a letdown, the bases are unergonomic chipboard rubbish and too heavy, the mirrors are poorly figured and mirror makers don't like refiguring them because the glass type has strains, the secondarys are cheap, poorly figured and nasty, the Alt bearings are way undersized, the focusers are coarse and sloppy, the design actually means the scope is poorly balanced, the mirrors are usually silastic glued to the mirror cell and induce astigmatism.

I personally think the manufacturers are letting the hobby down by cutting corners too much on these scopes. Most of the issues I've listed could be addressed by the manufacturers at a price point about double the current 1299. Sorry I hate to be a wet blanket but these scopes are a compromise layered on top of another compromise.

Quaoar - So what would you spend £1299 on?

Paul73 - It was my thinking that a dark sky & 16 inch would show fantastic views...I have used many 12 inch dobs but not as yet a 16 inch...I see what you are saying smaller scope in a dark sky showing equally great views for the money...so again the question would be how is the money best spent...This is hard work trying to decide what to buy...So much to think about

[Peter Drew]

As you might expect, I'd say go for it . The OP's location sounds ideal for a large Dobsonian.  Regardless of some deficiencies even a budget professionally made offering is usually better than most homemade attempts and probably costs less. I have used several entry level(?) 16" Dobsonians and have never been disappointed by the DSO views, a budget 16" will always show fainter objects than the finest 12".  I've used my self built 17" F5 Dobsonian for over 30 years, it gives excellent DSO views and first class lunar and planetary images, there is also the potential for off-axis masking as championed by Moonshane.

[quaoar]

If it was my money I'd invest the lot in the mirror. Decide on which mirror maker and order one. You're going to be in this hobby for life and you want the best mirror you can't afford. While you're waiting for the mirror to be made keep saving money and decide on which basic scope design you want, DIY, kit, secondhand or premium?. If I crashed back to earth tomorrow, lost everything and had to start again I would be scraping together the deposit on a Zambuto mirror however you have just as highly regarded mirror makers over there. I wouldn't take a GSO even if you gave it to me.

Unless you build it yourself, which is possible, (Swamp Things beautiful dob is an example) unfortunately if you want to go 16+ you are going to have to come up with more money. I know it's not what we want to hear but spending hard earned on rubbish is worse. The heart of the scope is the Primary mirror, start there.

[quaoar]

A friend of mine has just imported an Astrosystems telekit and is putting it together, it looks good so far although not finished. I am looking forward to checking it out. There is a fair bit of work putting these together but I am sure they are way superior to any GSO clone. I have an unassembled Dobstuff 16" kit myself that I have never put together but I can see just by looking at it that it too is superior to a GSO and certainly much more amenable to upgrading.

[Charic]

Exactly the responses I expected from the big Dobs, and warranted? and who wouldn't want the larger aperture. I'm fully aware of the larger image scale afforded over my 8", I have already considered a 12" or bigger myself, but its just not a practical solution for me, and even though I have funds available, its still a hefty  price tag, not including  extra EP's get the best out of it, and the list of negatives for me far outweigh the positives, so for me at present, it would be a no-go situation.

My comments were also on the basis that Astronolee,  having the basic 15x70s that I have ( cheap but not brilliant IMHO)  Its still an awesome amount of money  to dive into a 16" Light-bucket, with all its foibles and come out smiling at the other end . Doesn't often happen like that. I would suggest You need to build up to  this system. Also, "wanting to learn more about the sky"......no GoTo or tracking maybe? A lot of money for visual observations only,  and possibly,  someone relatively newish into the hobby. Yes, old enough to make his own mind up, but this is what the forums are for. Unless the 16" was the Rolls or Heineken of the Telescope World and it did everything  flawlessly, we have our opinions.  After-all, its only opinions.

My Skyliner is working against shaded street and neighbours light pollution at my observatory,  but I'm in awe when I go to a darker site, and yet, I've still not tried the darkest site where only Starlight is my  only illumination, available in the vast wilderness that is Scotland, but that's like planning a camping trip for me?  With this Year's weather, as were all experiencing, that trip is constantly delayed, but something to look forward to. Its mid August, I've already seen brown leaves on the ground, so Winter is just around the corner, which means longer nights ahead.

The 16" offers greater detail, but I don't need the associated issues. As always. you have to try before you buy. Thats possibly the hardest part to overcome. 

[Earl]

I use a 10 inch Dob it is the limit of what I can physically handle since having a stroke, but regardless of that id say the 10" is about right unless you are really into it using larger scopes and have the enviroment to make the most out of it.

If I wanted a better dob than my current id probbaly look at an Orion UK with better optics, but for me its really of no use, my SW250 with a few tweaks will do me fine for what i want.

[scarp15]

Whenever this Revelation scope comes up on topic on here it immediately becomes a 'hot potatoe' talking point. I guess it comes down to your budget, as there are many premium options to, such as through David Lukehurst etc.

It has been mentioned a couple of times concerning second hand options. Contrary to what has been said, do not rule out ebay. I have purchased two scopes through ebay, both very satisfying and the only way I would have been able to afford such an instrument. Yet as with committing to any second hand purchase, take time and consideration to satisfying all your questions via the seller.

I have had experience with a Skywatcher 300p flex tube, this was a terrific scope and making the upgrades i.e replacing the springs etc was part of the fun, so if you can get hold of a 350 or 400 version of this would be perhaps a further consideration.

[Caldwell14]

And I'd rather have a 12" 1/9th wave PV mirror in a scope that I can set up in 30 seconds than a 16" 1/4 PV (at best) one in a scope that's inconvenient for me to use to be honest Mike

Each to their own though

I have a small garden, a small cottage and next to no storage space. I had two sensible choices, a 10 inch Chinese Newtonian or 8 inch 1/10 wave PV. I went for the research grade optics. I have no regrets . The scope possesses very very bright, über sharp views and is beautifully built, and that maters to me

[Astronolee]

Exactly the responses I expected from the big Dobs, and warranted? and who wouldn't want the larger aperture. I'm fully aware of the larger image scale afforded over my 8", I have already considered a 12" or bigger myself, but its just not a practical solution for me, and even though I have funds available, its still a hefty price tag, not including extra EP's get the best out of it, and the list of negatives for me far outweigh the positives, so for me at present, it would be a no-go situation.

My comments were also on the basis that Astronolee, having the basic 15x70s that I have ( cheap but not brilliant IMHO) Its still an awesome amount of money to dive into a 16" Light-bucket, with all its foibles and come out smiling at the other end . Doesn't often happen like that. I would suggest You need to build up to this system. Also, "wanting to learn more about the sky"......no GoTo or tracking maybe? A lot of money for visual observations only, and possibly, someone relatively newish into the hobby. Yes, old enough to make his own mind up, but this is what the forums are for. Unless the 16" was the Rolls or Heineken of the Telescope World and it did everything flawlessly, we have our opinions. After-all, its only opinions.

My Skyliner is working against shaded street and neighbours light pollution at my observatory, but I'm in awe when I go to a darker site, and yet, I've still not tried the darkest site where only Starlight is my only illumination, available in the vast wilderness that is Scotland, but that's like planning a camping trip for me? With this Year's weather, as were all experiencing, that trip is constantly delayed, but something to look forward to. Its mid August, I've already seen brown leaves on the ground, so Winter is just around the corner, which means longer nights ahead.

The 16" offers greater detail, but I don't need the associated issues. As always. you have to try before you buy. Thats possibly the hardest part to overcome.

Thanks 4 all the comments...I am still no wiser tho lol...in your opinion go smaller then...maybe 12 inch or orion/sw...Charic was u suggesting get goto??...I am more confused now than when i posted the question...I am definately going to attend a few more star parties over the next few months but all those I have been to have only had up to 12 inch dobs...i guess that suggests something about portability...Although the new ES Dobs look pretty portable

[jetstream]

Thanks 4 all the comments...I am still no wiser tho lol...in your opinion go smaller then...maybe 12 inch or orion/sw...Charic was u suggesting get goto??...I am more confused now than when i posted the question...I am definately going to attend a few more star parties over the next few months but all those I have been to have only had up to 12 inch dobs...i guess that suggests something about portability...Although the new ES Dobs look pretty portable

The nice thing is that you have a lot of time to figure out your needs and find a scope that meets them.They make scopes everyday,no rush.If high quality planetary was desired I would research how cooling,mirror figure, sec obstruction,etc effect the image.Some people with big dobs also have a smaller scope at their disposal for various reasons.

Do you want an all 'round scope or a dedicated DSO or lunar/planetary?What is the EP budget,do you need a coma corrector,how is your (and your tools) collimation ability?Will a large field of view be important to you?

It may be better to have some of these questions answered before a large outlay of cash,to each their own though.

[Paul73]

A 14" OOUK 1/10 pv will set you back £3k!!!!!

Given that you are into the faint Fuzzies. Which by their very nature, are a bit fuzzy anyway, surely raw inches on a sturdy scope is the way to go??

If it has to be new, Maybe the SW 350p might be a good compromise for the same money as the Revelation? By all accounts, it is built like a tank and the optics might be a bit better than the Revelation's?

Why waste money on GoTo when it isn't a must have??

Thoughts anyone.

[Charic]

..........if you just compare a 16" to a 12" with an 8" in a field all set-up for you, your going to like the 16". It has the greater image scale, as users of the larger Dobs  have explained, and to some extent I do agree with them, but your in a crux. Get the 8" and you'll never know what the 16" beholds, yet spend all that money on the 16" and then come across a smaller DOB, solid tube,  and you may wonder why you needed the bigger system. Admittedly, the image scale is going to be a factor between the telescopes. but its only you that can make this choice. Listening to the good advice here helps, but your own hands on feely-touchy test of someone else's system will really help you to concede to your final choice. There are too many 'against' issues for me to purchase the 16", but I always state 'aperture is king' ( folk will argue this too- i love it! )

I'm a firm believer of manual operation. GoTo would be better if you were regularly displaying to School kids or displays somewhere, or just couldn't learn your way around the heavens! . I don't recommend a GoTo. that still requires careful set-up and alignment procedures. I've used an EQ mount, without any power whatsoever, I felt more time is wasted setting up with  continual adjusting than actually observing, so for me its a pain in the donkey, and I wont use an EQ set-up for visual use. When/if I venture into proper 'take my time interest in astro-photography( I have the kit)  then an EQ mount will be essential. I have little experience of other telescopes, eyepieces, and equipment. I know what works best for me, that, which is presented in my signature block. If your on a business trip to Inverness in the next month or so or a Ski holiday in Aviemore before Christmas, your welcome to try my telescope. I know you would be happy, after showing you on a clear night the difference between by garden observatory and from a darker site not too far away, the difference is so visible, like having a different telescope at the darker site. trying is the best method to get a feel and an insight. I never had that opportunity, but I will always advise that to others, as so many folk here advise too.  

[Rustysplit]

As you are only in Essex, I would give Telescope House a ring and go down and look at one. They have one in their showroom, or they did a couple of weeks back, post the move to their HQ. I have had a good look round one, not through I might add, and the mechanics seem very reasonable for the price. Actions are smooth and the alt bearing has some in built adjustment and adjustable brake. Get yourself along and have a look. Nothing to lose.

[Dude_with_the_tube]

interesting reading and interesting comments,i however,will agree with people who commented on quality of mirrors as these are the most important part of your scope,rest is just MDF sheets and tube what can be picked up in B&Q for few quid.(didnt mean literally)

Also i will agree on statement of getting out and seeing the scope in flesh before you commit yourself.

Aperture is the king and 16" or 14" or even 12" scope will show you much more then 8" scope any time.Planetary wise images will be much brighter,DSO will show far more detail as aperture goes bigger and no you will not need eye pieces costing 200+quid to fully enjoy the scope.When i had the choice between 14 or 16" i went for 14" as this is really the max i would be happy to operate as I set up my scope "solo" .I would love to have something in 20+ " size,but some other time

Get the scope you really want and main thing:the one you will be happy to use for your hobby and not as a thing stuck in corner of your shed and gathering dust

[ollypenrice]

We'd all like a Zambuto mirrror in our Dobs but you can't pay the postage from Carl's workshop to the UK for the price the OP is talking about!

Let's remind ourselves of John Dobson. Was he a prima donna scope fetishist for whom only a tenth wave mirror would do? He was not. He was a great man who wanted to bring faraway galaxies to the public on a budget. The big cheap Dob is an astronomical institution and rightly so. The question is, what can you get away with?

Olly

[Astronolee]

I've gotta say what a fantastic response to my question and at the moment i am 99% certain for the price i am going to get this scope...I was about to rush in but instead I will though visit Telescope House and spend the next few months going to star parties and seeing if I can get a look for real...If I cant then I may just buy it anyway ;-)...As long as I can get wheels on it and I can keep this fully set up I honestly think based on the research I have done this scope will surely give me the WOW factor I am after...I will definately keep you posted of what I end up getting...I will no doubt end up buying extras but thats what I want...A great base to start from and build on...I really am unsure the same excitment will be felt buying expensive EP's for an 8 inch plus there is no way I want/can buy Zambuto mirrors so for me personally this is not an option others might want to pursue. I am still convinced for the money the Rev Dob is great value :-)...For me its really a choice between Skywatcher, Meade, Revelation etc...IMO so far the Revelation 16 inch wins

[Charic]

.......carrying on from the PM's.  you did well to hold off on that  12"  offer ? There will be lots of offers like that popping up,  but just take your  time. You`ll make several folk envious when the 16" eventually arrives ?