GSO RC images 21 May 2009

[Peter Ward]

Originally Posted by dpastern

I doubt that many people are going to honestly be able to tell the difference between an image taken with a 12" GSO RC and a 12.5" RCOS RC. At least, when both units are properly collimated, decent mounts are used, good tracking, good exposures and the same CCD imaging gear. ........
Dave

That may well prove to be prophetic....but I'm still inclined to adopt a wait and see approach.

However I don't think the value of albeit less expensive, but good RC telescope, will affect RCOS anymore than a luxury Hyuandai would affect S-Class Benz sales.

A 12.5" optical set (from Star Instruments, the RCOS supplier) alone will set you back a cool $US6000..... Why? For starters the optics are Zygo tested and certified to 1/25th wave RMS, and have thermal properties an order of magnitude better (actually 20x better) than the fuzed quartz by GSO. (BTW this talk of 500% mark-ups is utter nonsense)

I applaud Paul's ingenuity. By adding a more robust and accurate focuser and adapting 3rd party field flattner to a modest scope, plus putting the ensemble on a top-of-the-line mount, he is indeed getting a great result!

But we are hardly talking about "cheap" systems out of the made in China box anymore.

[marki]

Originally Posted by Peter Ward

"And Meade’s 6” f/10 Advanced Coma-
Free (ACF) catadioptric optics deliver the
same sharp coma-free view as a professional
Ritchey-Chrétien telescope, but
without an R-C’s high price tag"

Come on Peter, you know it's true, surely you wouldn't question meades excellent and highly aggressive marketing campaign

Mark

[Paul Haese]

Thanks guys,

for this is all about having a go with an affordable solution. The mount, focusor, and flattener all enhance what looks like a good little scope. Certainly not an RCOS. I have checked other guys images, but I am happy to report that the images stack up well generally. That means there is room for improvement on the capture side and certainly from the processing side.

I like the fact that a person can buy a good OTA for 3k (including the focusor) and get nice sharp images. That is what is important. If you want to own a Roller buy the RCOS. If you cannot afford that, well this is a good option.

Once again thanks for the comments and thoughts.

[kinetic (Steve)]

I totally agree on the comments on mounts by Peter,

Here's a great post by MonteWilson that sums it up best:
http://www.iceinspace.com.au/forum/s...9&postcount=13

Steve

[dpastern (Dave Pastern)]

Originally Posted by Peter Ward

That may well prove to be prophetic....but I'm still inclined to adopt a wait and see approach.

However I don't think the value of albeit less expensive, but good RC telescope, will affect RCOS anymore than a luxury Hyuandai would affect S-Class Benz sales.

A 12.5" optical set (from Star Instruments, the RCOS supplier) alone will set you back a cool $US6000..... Why? For starters the optics are Zygo tested and certified to 1/25th wave RMS, and have thermal properties an order of magnitude better (actually 20x better) than the fuzed quartz by GSO. (BTW this talk of 500% mark-ups is utter nonsense)

I applaud Paul's ingenuity. By adding a more robust and accurate focuser and adapting 3rd party field flattner to a modest scope, plus putting the ensemble on a top-of-the-line mount, he is indeed getting a great result!

But we are hardly talking about "cheap" systems out of the made in China box anymore.

Peter,

I think it will affect RCOS, more so than Benz, simply because there is very little competition in RCs. In this day and age, people are looking at their dollars twice, three times, nay, 4 times or more. If I had the money, I'd probably buy an RCOS, because they are the best, there's no argument there. But - the GSO RC comes close, for a fraction of the price. Again, all this talk about 1/12 wave, 1/25 wave, etc etc - I honestly doubt that the average person could tell the difference between those 2 measurements in real life images. Again, like with another hobby of mine (hi fi), all these fancy measurements are great, but they generally mean bugger all in the real world, and that's *what* counts. I've been around far too long to believe that measurements holistically accurately describe the real world characteristics of something.

I don't begrudge you owning a RCOS (sorry if I sound that way, it's not my intention) - I simply dislike artificial pricing for the sake of making a buck because people are gullible enough to buy the item, instead of walking away from it when they realise that the item is way overpriced. I've spoken to a few people in private, and one person in particular used to work for RCOS and he guaranteed me that they have huge markups.

Dave

[dpastern (Dave Pastern)]

Originally Posted by kinetic

I totally agree on the comments on mounts by Peter,

Here's a great post by MonteWilson that sums it up best:
http://www.iceinspace.com.au/forum/s...9&postcount=13

Steve

Oh, I agree, I consider mounts the most important part of the equation. But, even the best mount will not be great if you don't accurately polar align, etc. I've seen people with Paramount ME mounts, whose images have been well, not very good. And they had expensive OTAs too. Just because you have an expensive item, doesn't automatically guarantee that you'll know how to eek the best out of it. Hell, I'm struggling to get 15 second images out of my very modest setup without trailing (and I'm currently losing the battle I might add). I'm sure that once I get my act together, I'll start being able to get better images.

Dave

[TrevorW]

And on the other hand I'm aware of several amateurs who have captured exceptional images with only modest equipment so taking the car scenario just because you may own a Porsche it doesn't make you a race driver.

Also like Peter said these scopes are not designed to compete with the likes of RCOS which are just in another ballpark.

It's like anything in life if you can afford the best then buy it otherwise make the best of what you can afford.

Pauls images show the potential of this scope and thats all.

[RB (Andrew)]

Originally Posted by kinetic

I totally agree on the comments on mounts by Peter,

Here's a great post by MonteWilson that sums it up best:
http://www.iceinspace.com.au/forum/s...9&postcount=13

Steve

Steve I agree, the mount is *the* most important piece of equipment as far as I'm concerned.
Followed closely by the person's processing skills once they've gathered the data.

Around the forums I've seen lots of people spend a lot on scopes and camera gear, only to be let down by their processing skills.

At the end of the day it basically boils down to what you do with your data.

As for the GSO's, it's nice to see they have the potential to perform.

[Peter Ward]

Originally Posted by dpastern

..... the GSO RC comes close, for a fraction of the price. ....
Dave

Sorry Dave, looks to me like you have a "tall poppy" attitude to RCOS.

Close?

......so, GSO has ion milled zero expansion optics with .96 strehl or better? an absolute position focuser re-produceable to 1/50,000th of an inch *and* tracks focus with temperature changes? Ultra rigid carbon fibre truss that delivers ~20 arc sec all sky pointing? Primary, Secondary and ambient temperature probes and thermal control? Adjustable primary, secondary and baffle? High torque 1/100th of a degree instrument rotator option? dedicated 70~120mm wide field flattner? External Stepper remote control...plus all of the above controlable via a local PC, network or internet?

Of course it doesn't, and all of the above costs $$$

But it's a great little scope...and represents an excellent solution for many....but I'd suggest it's still not a Benz

[AlexN]

Well said Peter.
The RCOS are expensive, however they represent a whole new level of control and monitoring over the telescope system. The cost of all the electronic extras is half the reason they are so damned expensive, although to some users who are setting up remote observatories, these are requirements. The RCOS scopes fully optioned are an unparalleled imaging platform..

The GSO is a very nice compromise for those of us who dont require ion milled optics, temperature controlled focus or telescope command center.. (I wouldnt mind a RCOS instrument rotator though!! )

[jase (Jason)]

Lovely images Paul. Kudos to you for the effort you're putting in. Saw those reflections in the other post - interesting. I'd probably be focusing on the secondary light shroud/housing. Perhaps create an aperture mask and tape it on to see if that alters the situation. Keep at it.

Wha!! Why are people comparing an RCOS RC with a GSO RC? Different league all together. Sure they share the same optical design, but that's where the similarities end. A more comparable RC to the GSO would be those produced by Deep Sky Instruments - http://www.deepskyinstruments.com/products.htm. Personaly, I'm keeping an eye on their 14" expected to be released soon. Sure, these are more expensive than the GSO's, but you pay for what you get. The name "Ritchey-Chrétien" does not insist optical perfection - RC's are not all created equal!

If you're going to make comparisons with an RCOS RC, you'd want to be comparing it against something like the A&M RC's - http://www.astrotechengineering.com/Default.aspx?ID=156.

[bluescope]

Nice images Paul ... especially 5128 ... everyone seems to have bogged down in a debate about gear again when what really counts is the images and your enjoying your hobby



p.s. The only comment I would make about the 5128 image is why is the brightest blue star below the galaxy seemingly slightly out of focus i.e. the spikes aren't aligned ... all the others are fine

[dpastern (Dave Pastern)]

Peter - let's take a step back and look at things.

1) Paul has been able to get some fab images without all those "extras".

2) said images look good to me.

ergo one can deduce that:

3) said extras aren't entirely necessary - one can grab quite nice images without them. Sure, if they float your boat, go for it. For me, and I suspect, many others, they don't.

Do I need the kitchen sink with a scope? No. Do I want it? Not really. Can I afford it? No. Can I justify X amount for a RCOS? No. Not when alternatives can do what it does, for a fraction of the cost. People insist on being silly and apportioning quality to a brand name, and it's dangerous. Brand name does not equal quality, well not always - there's no guarantee. As a society, we're so heavily taken by "image", that other things tend to be ignored. I ain't one of the Joneses (if you haven't noticed by now lol).

Dave

Originally Posted by Peter Ward

Sorry Dave, looks to me like you have a "tall poppy" attitude to RCOS.

Close?

......so, GSO has ion milled zero expansion optics with .96 strehl or better? an absolute position focuser re-produceable to 1/50,000th of an inch *and* tracks focus with temperature changes? Ultra rigid carbon fibre truss that delivers ~20 arc sec all sky pointing? Primary, Secondary and ambient temperature probes and thermal control? Adjustable primary, secondary and baffle? High torque 1/100th of a degree instrument rotator option? dedicated 70~120mm wide field flattner? External Stepper remote control...plus all of the above controlable via a local PC, network or internet?

Of course it doesn't, and all of the above costs $$$

But it's a great little scope...and represents an excellent solution for many....but I'd suggest it's still not a Benz

[AlexN]

Agreed Steve, Good call... Who cares about the brand name or optical design. If the gear is producing images that you're pleased with, then its good gear... Doesn't matter if it cost $30,000 or $3000.


Dave - In the case of companies like RCOS, Planewave, Astro Physics etc, The Name brand only got the reputation that they did by making exceptionally high quality products with very low tollerance for error. The quality actually is gauranteed from names like the afforementioned...

[Peter Ward]

Originally Posted by bluescope

Nice images Paul ... especially 5128 ... everyone seems to have bogged down in a debate about gear again ........

Agreed.

The merits of various scopes (which I'm always happy to discuss) should be taken up elsewhere.

[pgc hunter]

fantastic! Loving the Trifid and Eta Carina shots!

[dpastern (Dave Pastern)]

Originally Posted by Peter Ward

Agreed.

The merits of various scopes (which I'm always happy to discuss) should be taken up elsewhere.

Yes, perhaps it's better to do that :-) I didn't meant to offend you Peter (hopefully I haven't). I just simply have one particular point of view that differs to yours.

Dave

[AlexN]

Dave, I wouldnt worry. To my understanding you can't actually offend Peter.

[EzyStyles (Eric)]

Fantastic images Paul! Definitely up there with the rest. I have seen you come a very long way. Your effort, dedication and commitment have produced these images

Hi Steve, the twin spikes in 5128, theres 2 bright stars next to each other. nothing got to do with focusing .

In terms of equipment, do the best of what you can afford the GSO RC might be one on my list soon.... .thanks Paul

[strongmanmike (Michael)]

Three very excellent images Paul after some initial frustrations I bet you are pretty happy sitting at your computer looking at these



Mike