New GSO 10 inch RC

[bmitchell82 (Brendan)]

hahaha lipstick on a pig, reminds me of those.. whoopsys i wont go there

[rat156]

Originally Posted by jase

Its all relative Paul. I'm not going to deny that the US and European manufacturers are expensive, but they are also spending at least six to eight fold in time to build scopes compared to the Chinese or Taiwanese counterparts. As you say, the latter is mass produced, quantity over quality philosophy. Robotic arms instead of flesh and bones driving greater profit, but improved quality? hmmmm maybe with time?

So who wins? You buy one of these scopes, have to spend more money and commit your time to resolving matters which should have technically been addressed through R&D and QA. You've had your fair share of troubles as have others and I'm sure this has come at a cost. Alternatively, you pay more for an established instrument and get close to a turn-key imaging solution, be it minor tweaks to get it humming along. If the Chinese or Taiwanese manufacturers spent a similar quantity of time as the others, prices would climb, so its a trade off.

For the money that is out laid, the results are what I would expect and as such I'd be happy. Obviously everyone has different expectations. Whether they are realistic and obtainable is another discussion. With such a vast difference in quality between budget, mid spec and top end RC's, one can only compare results of a similar breed RC, so my previous post in reference in the 10" RCA is moot. The RCA series and those from deepsky instruments are mid spec instruments as opposed to the budget RC's coming out of China or Taiwan. What I was attempting to allude to however is that paying that bit extra can yield vastly different (superior?) results.

I want to be clear that I'm not attempting to put people off purchasing budget RC's. In many cases, they'll probably meet your goals and you will be happy with the output. There is a strong market for such instruments which will thrive with time. I do however suggest people review the facts and manage expectations. Comparing the differences between a 4k and 12k instrument can be the difference between night and day, no matter how much time and money you sink into getting the 4k instrument working. Its putting lipstick on a pig.

I think that some of the points made here deserve closer scrutiny. The "quality" of images depends on much more that the quality of the optics. Firstly we should define what we mean by quality of images. There are some measurable parameters which I generally grade images, in particular sub-exposures for inclusion or exclusion in a final image.

The first thing I look at is the roundness of the stars. This is mainly influenced by the tracking of the mount. Barring any optical faults the roundness of stars on RC's af any brand are really good. The GSO RC has excellent roundness all the way to the edge of the field of my ST-10. I don't have an expensive RC to compare with, but there are many images to which I can compare. The quality of the optics are relatively unimportant wrt star roundness.

The FWHM of the stars, particularly a change between the centre and edge of the field. This can be influenced by many things, focus is king though, if the GSO is in focus I believe that it will produce stars with the same FWHM as any expensive RC. By far the greatest influence is your local seeing. The quality of the OTA will influence focus, as if the camera can be easily skewed, or the focuser is not up to taking the weight of the camera then this will make focus difficult to obtain and then hold. This is easily remedied by an aftermarket focuser, so add $500 to the cost of the GSO. If you know beforehand this is no big deal. I would not expect any of these problems with an expensive RC.

Optical defects can occur in any scope. They should not be allowed out of the factory, whether that be a big or small factory, obviously the more you make the more likely that one will slip through. GSO have proven to be very good about taking returns of defective scopes and replacing them. Astigmatism and field curvature are properties of the design, not how well the optics are made. The Strehl of the expensive scopes is almost certainly higher than those of the GSO scopes, but how high do you need to go?

Image depth is certainly one area that the optical quality of the scope can influence. Do the images produced by the expensive RCs have greater contrast? Is this more likely to be due to more longer, deeper subs from dark skies? I say yes and yes to both of these questions. I find that when the image contrast of a picture is greater than mine the photographer has taken more or longer subs. The scopes vary from refractors to various reflectors. The main problem with comparisons is that owners of $10k+ scope generally have them at dark sky sites on super mounts, not like the rest of us from a suburban location on a not quite so good mount.

I'm not saying that the expensive RC's are a waste of money, but for 5-10 times the money of the GSO variety they should be like chalk and cheese. They are not.

For the money you can't do better IMHO, bring on the 10", I can't wait, then the 12" version. If they are rubbish we'll know soon enough and I'll just have to make do with the 8" version.

Cheers
Stuart (Smearing lipstick on Bacon)

[Zaps]

Originally Posted by jase

Comparing the differences between a 4k and 12k instrument can be the difference between night and day, no matter how much time and money you sink into getting the 4k instrument working. Its putting lipstick on a pig.

This reminds me of the arguments of the Astro-Physics fanatics back home. For them it was Astro-Physics or nothing, no matter how much logic and reason was proffered. Yet I have to think that if Astro-Physics wasn't an American company, those same fanatics would have no interest in it.

At least 99% of their stance was based on patriotism and flag waving. Most of them never let their precious telescopes leave their den or dining room anyway. That is if they hadn't already sold it and made a profit before it was delivered to them.

For the record, in my opinion, there aren't many $12000 telescopes that are $8000 better than a $4000 telescope. There may be none that are $8000 better. Looks like some people don't think an $8000 brand sticker is overpriced, I guess.

But speaking for myself, I'd happily save that money and buy a "junky Chinese made clone", then slap a few upgrades on it. The end result is a telescope which performs as well as a dining room display model but for a lot less cost.

[Paul Haese]

Originally Posted by jase

Its putting lipstick on a pig.

ROFLMAO. Mate that takes me back to my time in Sydney as a lad. Don't worry I'll tell you some time.

I am well aware that eventually I will buy another telescope to further my goals. I fear though that many premium telescope makers will eventually outprice themselves and leave their scopes to the rich man just as it was years before.

[TrevorW]

I've so far kept quite but just can't help myself:

1. I'll never unless I win Lotto afford an El Capitian or RCOS or an SBIG 11000 SXYZ top of the range camera
2. I may be able to afford a reasonbaly priced G11 and similarly priced CCD Cooled camera some time in the future
3. So far the problems with my images have been depth, noise and roundess of stars plus the inevitable tracking induced elogation errors etc
4. and lets not forget that the seeing conditions play an all too important part in the final image quality

However is saying this like others I have rec'd favourable responses from numerous people on a number of forums on the relative quality of my images (please don't take this as bragging cause I'm not)

So improving on the obvious faults in the long run should lead too far better images.

Whether you spend $2000 or $20000 on the optics if the other variables ain't right it ain't going to make an ounce of difference.

So for those who can't afford a RCOS, Star Instrumnet or Planewave then the GSO RC's offer an affordable alternative as far as I'm concerned.

[gregbradley]

I've been impressed by some of the images from the 8 inch. Paul has shown that. If you can sort that star elongation at the edges your laughing. A flattener of some sort should do the trick.

They do represent good bang for your buck, kind of like a Subaru WRX telescope.

The Vixen VMC260 is an interesting competitor. I'd go the Vixen as the trend nowadays is for corrected compound scopes like ASA Newts with the Keller corrector, Planewave CDK with its doublet corrector, Ceravolo
corrected Dall Kirkham, Hyperion - corrected Cassegrain. The A&M RCs are good bang for your buck too for a carbon truss RC but they also need a flattener that they sell. They also have a nice reducer. So does Planewave now. This area of the market is heating up with Meade ACF and now Celestron HD optics. There's a lot of choice and some very nice gear on offer.

These RCs all need flatteners to sharpen up their star sizes off axis although the 12.5 inch RCOS I had did very well without it.

Greg.

[dpastern (Dave Pastern)]

If I didn't know any better, I'd say that there was a slight focus issue, and some warping of the imaging plane in his images. Compare it to the other Astrograph images from the other 10" manufacturer that he's testing and you'll see that they're sharper, more tightly focused and less elongated.

I'm thinking possible figuring issues with the primary and secondary, with innaccurate (ever so slightly) distances between the 2.

Dave

[Peter Ward]

Dealer hat off for a bit...

What many people don't get is: with any engineering, the first 80% is pretty easy.

For example, GSO make a fine product as it represents great bang for buck, but frankly they are not an RCOS or AP.

Think of audiophile systems (I rather like JBL or Klipsch monitors)...or cars (I have a penchant for stuff from Stuttgart and Prancing horses )

The reality is most Hi-Fi's give you a good sound, or cars a comfortable ride from A to B

But it you want flat line 20-20KHz audio, or 0-100km in under 4 seconds....it *costs*

Why is it a revelation that with optics *you also get what you pay for*?

Sure, with anything that lends itself to *consistent* mass production quality can go up for a lower cost...but machines can only do so much.

You might buy a Casio watch that is good to 1 second per month. Yet the next one of the shelf is only good to 2 minutes....the question is: is it reasonable to expect 1 second accuracy? A Breitling is guaranteed to give you that 1 second, plus a really snazzy case, and then some...but costs 10-50x more.

The GSO RC10" scope will not be unlike the current RC8", but with a bit more aperture and FL, and I'm sure for many will fill that "sweet spot" of price/performance .

But if you want that last 2%.... just move along

So endeth the lesson.

[dpastern (Dave Pastern)]

Peter - few speakers go down to 20hz I'm afraid. Most roll off around 35hz. Certainly, smaller, studio speakers, do not go down this low, they do not have the volume to produce the longer wavelengths for such low frequencies. And it's not so much the higher frequencies - 20khz isn't hard to do itself, it's how it's done. Odd or even harmonic distortion?

And yuck to JBL or Klipsch I might add.

Sorry, just couldn't resist since hi fi is another hobby of mine.

Dave

[Peter Ward]

Originally Posted by dpastern

....

And yuck to JBL or Klipsch I might add.

Sorry, just couldn't resist since hi fi is another hobby of mine.

Dave

Heretic!

Klipsch Corner horns (do they still make them??) *do* go down to 16Hz ......slightly higher for my JBL 4315 Studio Moniotrs (no longer made).
(fingers in ears) I will not hear *any* critique of these classics!

Newer is not always better!

[Kal (Andrew)]

Originally Posted by Zaps

This reminds me of the arguments of the Astro-Physics fanatics back home. For them it was Astro-Physics or nothing, no matter how much logic and reason was proffered. Yet I have to think that if Astro-Physics wasn't an American company, those same fanatics would have no interest in it.

At least 99% of their stance was based on patriotism and flag waving. Most of them never let their precious telescopes leave their den or dining room anyway. That is if they hadn't already sold it and made a profit before it was delivered to them.

For the record, in my opinion, there aren't many $12000 telescopes that are $8000 better than a $4000 telescope. There may be none that are $8000 better. Looks like some people don't think an $8000 brand sticker is overpriced, I guess.

But speaking for myself, I'd happily save that money and buy a "junky Chinese made clone", then slap a few upgrades on it. The end result is a telescope which performs as well as a dining room display model but for a lot less cost.

Since you want to bash AP I'll provide you with a few words from Roland to ponder, and ask why exactly are these chinese made RC scopes popular? Is it because of the performance, or is it simply because everyone see's expensive RC's and want these chinese made ones simply because they are relatively cheap?

What we tend to have in the astronomy world is a bunch of little mini-revolutions. It used to be that one got either a long focus achromat or a Newtonian of longish focal ratio. That was normal some 40 - 50 years ago. Then along came Celestron, and the whole ballgame changed. These scopes were compact and user friendly, with enough aperture to make things interesting. Then came Dobson, who said bigger is better, so everyone jumped on that bandwagon. Then along came the apo refractor, which promised a refined image and good astrophotography potential in a smaller aperture. These kind of co-existed and were developed to more and more exacting standards. Then came the large RC imaging scopes when the CCD camera displaced film. Now we are in the era of Chinese cloning of all these types at a low cost level, but not yet advancing the state of the art.

You ask whether any other scope type exists that can achive almost perfect performance for $1400. Yes, I believe such a scope is possible to make. If I were to decide to wade into this area, I would go back to basics to design such an instrument, and it would not be a Cassegrain. I would start with a basic medium fast parabolic mirror, maybe 8" F5 or F6, add a simple 2 element coma corrector. Both optics are fairly easy to make, and the primary mirror can be produced to a fairly high level of accuracy (the coma corrector does not need fancy corrections). A smallish secondary obstruction of around 35% should be able to cover most CCD chips, and produce a nice flat coma-free field. Of course one could go nuts and make it super fast, but then the cost goes up.

Why is such a thing not made today? Probably because large expensive RCs are being used by advanced imagers to produce some really incredible images, thus these scopes are hot! So the world of marketeering is simply using this hotness to promote a smaller, more affordable instrument. Why not a similar Newtonian with dedicated coma corrector/flattener? Because it's not as sexy sounding as an RC, it's not hot. Why are large scopes RCs instead of cheaper to make Newtonians? Because they are lighter and shorter and require less mounting brute force than a large Newtonian. So, round and round we go. We love the large RCs, but can't afford them, so we lust over one that is affordable. But it may not be the best choice for a low cost very high performance imaging system.

source

[dpastern (Dave Pastern)]

Uggh my bad Peter, you are, of course correct - Klipsch horns, like most horns will go down that low. To be fair to me, you didn't mention horns in your original post, you said monitors (they are 2 different things lol as we both know!!!).

My REL subs go down to around 12hz (-3db) when positioned properly, and in a decent room (which is also large enough to handle the larger wavelengths). Sorry to hijack the thread lol!

and old isn't necessarily bad, I never said that. I still prefer LPs to CDs. And valve amps to transistors.

Dave

Originally Posted by Peter Ward

Heretic!

Klipsch Corner horns (do they still make them??) *do* go down to 16Hz ......slightly higher for my JBL 4315 Studio Moniotrs (no longer made).
(fingers in ears) I will not hear *any* critique of these classics!

Newer is not always better!

[Zaps]

Originally Posted by Kal

Since you want to bash AP

Friend, nowhere did I "bash" A-P. Maybe I did bash the attitude of Astro-Physics fanatics, but honest folk admit they deserve it, because what goes around comes around.

What I did say was that few if any $12000 telescopes are $8000 better than any $4000 telescope. I guess when someone's paid that much money they don't want to know or believe that a $4000 is as good, or almost as good as their $12000 telescope. And if that $12000 telescope never leaves the display wing of the buyer's home then the buyer should keep his mouth shut about the merits of other telescopes which are probably out in the field being used. If the buyer is just another flipper, then they definitely have no place criticizing the telescopes of others.

You don't see a lot of that display-or-profit mentality here Downunder, but it's the most common one in the USA when we're talking about Astro-Physics telescopes. To each their own, yes, but those collectors and flippers are also the most vocal critics of other manufacturers, which says a lot about the artificially-generated mystique of Astro-Physics stuff: A ten to twenty year waiting list for small refractors or compound telescopes? Gimme a break.

Take an "inexpensive" off the shelf telescope, maybe of Chinese manufacture. Add a bunch of aftermarket accessories, like a Moonlite or Feathertouch focuser, etc etc. Pretty soon you have a telescope with optics not far short of a $12000 telescope, maybe even equal to one, and the nice mechanicals to boot. How much did that cost? How long did you have to wait for it? How much pleasure and use are you getting from it out under the stars while the $12000 boys are inside inspecting their OTA with a magnifying glass looking for dust motes?

[Kal (Andrew)]

Originally Posted by Zaps

Friend, nowhere did I "bash" A-P. Maybe I did bash the attitude of Astro-Physics fanatics, but honest folk admit they deserve it, because what goes around comes around.

I've been a member of cloudynights as long as I have been a member of iceinspace. I'm also a regular reader of Astromart forums, where all the bigwigs of astronomy manufacturing post. I'm a member of more yahoo groups than I care to remember. This stereotyped AP owner that you talk about is not a common thing. I saw a guy sell a takahash TOA-150 that was used once and only 3 months old the other week. I guess if that was an AP owner they would instantly be labelled a flipper. Yes there are flippers out there, but if you search how many GT's have been sold or auctioned on amart then you will not even find a dozen, and Roland is onto making his third batch right now, so there are 200 out there in the hands of owners. Less than a dozen sales, even if we assume all are flippers, means that 95% of owners are happily keeping their scopes, and I'm sure there are far more of those being used than being displayed in dining rooms as trophies.

Getting onto my second point, you still didn't mention why you thought these chinese made RC's are popular. I still contend that if it wasn't for the $10K+ RC's made by the likes of companies like RC optical, then there would be zero market for these cheap RC's. Their popularity is driven by consumerism wanting something that is generally expensive, simply because it is cheap. Their popularity is not driven by their performance. That does not mean that they can't perform well, but I still question why these 300 on the boat to the US will likely sell like hotcakes when the only astrophotography I have seen by them shows bloated stars.

[Moon (James)]

It looks like the push-pull screws on the back of the 10" have moved out towards the edge:
http://www.atscope.com.au/gsorc10scope.html

Compared to the back of the 8" where they are around the focuser.
http://www.gs-telescope.com/content.asp?id=149

[dpastern (Dave Pastern)]

The 10" isn't carbon fibre?

Dave

[Paul Haese]

Kal bloated stars is not a function of the optics it is a function of the sampling. I have 0.68" per pixel and the stars appear bloated. Peter took an image of the lagoon earlier in the year with a STL11000 and his sampling rate is much better with that camera and the stars had nice non bloated stars. He is a skilled operator and the image looked just like any other RC image. It is the camera verses the focal length that produces stars like that. Refractors suffer from the same thing.

The reason these scopes are popular is that they afford sharp views for the image scale. It is next to impossible to buy a refractor at present that gives the same image scale for galaxy imaging that an folded design can. If a telescope can give sharp views and do basically what you want and it is cheap are you telling me you would rather pay more money for a telescope that cannot do all that??? I have looked through an AP or two and yes they are nice but they are no better than a Tak and at least they are cheaper and you can get them sooner. I agree with Zaps a 10 year wait list for 6 inches of aperture at best is well odd. I can sense a lot of fear in your post about Chinese imports. The gear coming out of China and Taiwan now is very good, and it is affordable to the average punter. That is why people are buying them. It means you can get a descent astrograph without having to save for years, and that is not to mention all the spare parts one has to buy that are expensive too. I think it is a good thing that people want them, they want affordability.

[Satchmo]

Originally Posted by Paul Haese

Kal bloated stars is not a function of the optics it is a function of the sampling. I have 0.68" per pixel and the stars appear bloated. Peter took an image of the lagoon earlier in the year with a STL11000 and his sampling rate is much better with that camera and the stars had nice non bloated stars.

I would have thought bloated stars were due to a number of possible factors including optics, guiding, collimation , seeing conditions , processing , mount stability and sampling size, and could be a complex mix of all of these things. Would a Kodak KAF 8300 chip be better choice to get sharper stars due to small pixels and large numbers of them .

[Paul Haese]

Just to illustrate my point about bloated stars here are some from the AP gallery. Seems some of their scopes are perhaps defective due to bloated stars.

Image one

Image two

Image three

Image four

Pixel size makes a huge difference to how stars are shown on any image.

[Paul Haese]

Mark yes there are lots of factors which cause bloated stars. However the KAF8300 chip has small pixels which causes over sampling and this commonly (all other things being equal) causes bloated stars. DSLRS also have small pixels too and this also leads to bloated stars. Most of the images taken so far have been with camera's with small pixels. Stuart being the exception at present with the ST10

If the optics are inferior then all the stars will have a bloated appearance not just the brighter ones Mark.