Gso rc 16" F8

[Tandum]

Prices are up on Andrews. $5K for CF.

[brian nordstrom]

Woaw ! Robin thats a lot of scope for not much money , hope some one here gets one soon so we can hear all about it .
Brian .

[LewisM]

Being impressed by the results of Allan Gould's 10" GSO, I am tempted myself... 10", not 16"

[Peter.M]

There is one issue with this scope that I think GSO may have shot themselves in the foot with. Anyone with a mount capable of carrying it will also probably prefer to put a more premium scope on it :shrug:.

[allan gould]

Not necessarily. The SW eq8 would be a great platform especially running eqmod. I keep tempting myself with this option.

[h0ughy]

wow now that is an option - i have the titan and soon the eq8. taking the 14" meade lx200R but another 2 inches........

[Paul Haese]

Good price and no doubt the optics will be good. Where I think GSO need to go though is teaming up with a decent focusor and using truss designs for scopes in the 12" and up sizes. As many will know I have an RC12" and I think while the scope is good for the price it could be much better. Some structural enhancements such as I have mentioned could really draw patrons away from the more expensive manufacturers.

BTW I will not be buying a 16", someone else will have to do that.;)

[Peter.M]

The million dollar question, do we think the eq8s pe will be up to the task at 3200mm?

[Satchmo]

I think the EQ8 will probably handle the RC12 well ( which so far doesn't seem to have fired a shot in the market ). A mount capable of handling the 16" is probably a few years off ( EQ10 ?)

[Paul Haese]

Are you referring to the mount or the scope? If the scope then we have been through this. Click here (http://paulhaese.net/NGC253.html)for an image. If the mount then I have not heard of anyone buying one yet or much less imaging with one.

[Satchmo]

Yes hardly any sold and comparing to shots with Newts the results are pretty average ;) Imaging at 2500mm focal length is not a popular passtime.
You have a Paramount to mount yours on - most people who can afford a GSO RC cannot afford a Paramount.
I expect that more RC12's will sell when the EQ8 comes out , but that the EQ8 won't adequately hold a 16" RC .

[allan gould]

There is this from a Dutch site where those in cloudy nights forum were alluding to it being the new GSO 16" RC.
http://www.robtics.nl/product_info.php?products_id=3894&pID=3894&language=en
You can see on the Robotics home page that they are claiming the 10" GSO RC under their own brand name
http://www.robtics.nl/

Should sattisfy your requirements Paul.

[h0ughy]

but it is built for 50kg - so lets go the 2/3 rule - thats over 30kg:question: the 14" meade is 24kg i think

[Peter.M]

I have read the GSO rc12 is 22kg. Add a camera to that and all your other bits and bobs and your probably getting close to 30kgs. Another 4 inches of mirror and the additional tube weight I would hazard a guess the RC16 weighs quite a lot.

[Paul Haese]

If only they had bodies for a RC12. That would suit me. I might have to contact Brett to see who he got to build his Vixen into a truss.

[clive milne]

Come on Paul, that image is hardly a convincing validation.
Considering the gear you have at your disposal, you should be able to do way better than that.

For example, have a look at this image taken by David Plesko using the same camera and mount. David had the advantage of slightly more aperture (14" versus 12") but took this from a location where the galaxy doesn't rise more than 35 degrees above the horizon where as for you it should come close to directly over head.

http://www.billionsandbillions.com/images/astropics/Large/NGC253_large.jpg

David's image is in a different league... this is not consistent with what you are hoping to imply.

[Paul Haese]

That is funny Clive. This goes to show little you actually know about imaging.

First off, that scope is close to 20K and I never said these scopes were as good an RCOS. Secondly, and importantly this image was taken with an AO-L. My image is taken without an AO-L. If you knew what an advantage this has in imaging at long focal lengths you would not have embarrassed yourself Clive. He also uses focusmax for his focus. I did not do that for my image and am working on this for my RC12 now. Not only that this image you put up has had a lot of deconvolution applied to it and I can see it because I know how to process images, not seen you do that before. For the equipment David uses go to this site (http://cherrymountainobservatory.com/images_detail_multiples.php?id=122&iname=NGC253 - The Sculptor Galaxy). Off you hop now and go back to where it is you came from. :)

[Tandum]

I read on another forum that Skywatchers facebook page says the mounts are ready to go so we should see some soon.

[netwolf]

Awesome price.

Wow and so much cheaper than US, 2000 less.

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5830739/page/0/view/collapsed/sb/5/o/all/fpart/1

[bert]

I would have to disagree with this point. The paramount second hand is getting down (on astromart) to around 8k. This present excellent value for money. I imaging a lot of prospective 16 owners will be buying paramounts.

I expect to pull the trigger on a rc16 when they are due to be released. Can't wait, in fact I have most of the imaging train sorted out ready to go on one of these babies.

[Peter.M]

Its sad that being a young person on this forum I can't tell if Clive is trolling or not. The image presented by Dave is on a different level acquisition wise (probably due too factors Paul mentioned), however the processing leaves a lot to be desired.

Pauls image is also his first effort with the RC12 (i believe), it was guided with an external guide scope, and no flatterer was used. Those factors alone would contribute to the image capture quality.

[netwolf]

Paul

I think this is the Vixen Truss you are refering to.
http://www.iceinspace.com.au/forum/showthread.php?t=45537&highlight=vixen+truss

Also these 12.5" RC truss scopes using StarInstruments optics.
http://www.iceinspace.com.au/forum/showthread.php?t=39552

All are just fantastic works of Art.

[bert]

Wow, big call.

Thats Warren Kellers work, I have seen his processing work and it is stunning. I have thrown some ordinary data at him and he has made a proverbial silk purse out of a sows ear.

[g__day]

So to properly carry a scope of this size I'd guess you are into the AP1200 or PME class of mounts - you'd be above the $14K round!

[bert]

Don't forget:
Camera
Filter wheel
Focuser (the oem will be a joke)
Guiding setup and camera
Rotator
Adaptive optics
Reducer/flattener
Adapters
Collimating tools

[rmuhlack]

while we're talking entry cost, what camera would be appropriate to pair with such a scope that would give an appropriate image scale?

Using a 0.7x field corrector with a 16803 chip still gives an image scale of 0.83 (borderline...?) At the native FL would you need to use something like a e2v CCD 42-40, which with 13.5 micron pixels still only gives an image scale of 0.87. That's a heck of a lot of camera.

:shrug:

[Peter.M]

This is not a personal attack on Warren. What I am saying is if you look at that image it is over sharpened. The edge of the galaxy especially to me looks noisy and over sharpened.


My statement still stands that GSO made a mistake making this scope because anyone who can afford to make it work to its full potential will buy an rcos or cdk.

[Paul Haese]

Totally agree, does doomsayer do works for commission? Not being a machinist and not having the tools to do this work is not going to help. Lovely gear.

[netwolf]

Paul in his Vixen thread he mentioned possibly doing this for others.

[bert]

I'm not so sure...

Im pretty sure that RCOS has shut up shop, and the cdk17 runs around $25k, add an ascension 200hr and you are at close to $50k.

Think about this, new pme is around 13k, gso16 at around 5k. 18k compared to the nearly 50k for the planewave setup. I'm not knocking planewave either. I have installed a cdk24 fork for a friend and I think they are wonderfully made and present good value, that said Im not going to hand over 25k over for a cdk17. I am however willing to spend $5k on a gso 16.

I'll bet they will not be able to keep up with production.

[bert]

Ahh no, He does it for a hobby and he does not have his machining setup at present.

And yes they are works of art. Guy made one of those vc200's for me.

Even if he did still do them, the amount of work that goes into them is astonishing.

[Paul Haese]

That is a shame.

[clive milne]

Hi Pete, I find myself with a rare idle moment so I'll take the time to clarify a few things. The reply that Paul submitted also warrants a response which I will include as well.



The point that myself and Mark have been making is that no one on the web has published images taken through an RC12 that demonstrates the limit of its native resolution at prime focus. Paul's list of mitigating factors doesn't invalidate what we are saying, if anything it strengthens our argument. As for the processing, we aren't discussing the relative aesthetics of the images, just the acquisition of the raw data which is on a different level as you noted yourself.



I may be wrong, but I think it is the ONLY image taken through Paul's RC12 visible on his web page. The question that others have asked is is there something to this? After all, word has it that Paul was given a discount on the purchase price on the understanding that he would put it through its paces and post a thorough review of the telescope.... After two years, his best (only?) result by his own admission suffers from focus &/or tracking errors.


Paul's web page suggests a QSI OAG + Orion starshoot autoguider.


Ritchey–Chrétiens have strong field curvature, this is true.
It is also true that they are diffraction limited for a good portion of their field (axially). So this cannot be used as an excuse for a reduction of image sharpness in the centre of the field.


Contribute, perhaps.... anyway, here is a bit of an introduction to the effect of field curvature in RC's... You will quickly see that this isn't the problem with Paul's image:
http://www.dreamscopes.com/pages/projects-04/ccvrc-07.htm
(The orientation and magnitude of the blur circles are not consistent with field curvature)

Now, on to Paul's reply.
Here it is in full (for context):



Now deconstructed.


Paul doesn't actually know how much I know about imaging but invites you to believe he is an authority figure on the subject. Implicitly, the substance of our words is irrelevant. Paul is to be considered a trusted source of information... clive is not.

fwiw) If you have followed this forum over the last year or so you may have come across threads where Peter (Ward) and myself have held differences of opinion. Notwithstanding the intensity that the discussion oft times reaches (spirited would be one way to describe it) Peter has never once resorted to an appeal of authority even though he is one of the most experienced and skilled imagers in the country (if not the world) But I guess Peter has been around long enough to know my background on the subject.



Well, until we see an image that taken with an RC12 that is accurately focussed and accurately guided (yet to happen) we can't actually know how good they are..... My point from the beginning.
Incidentally, I actually do believe that an RC12 (assuming the optics are even half way reasonable) should be able to produce an image indistinguishable from an RCOS 12. I think the difference is in the fact that the RCOS will do it straight out of the box, the RC12 has mechanical issues that hold it back.




'dog ate my homework'
The truth of AO is that (unless the mount has gross drive errors) it will tighten your star images by 20- 30% at best.
ie):
http://www.optcorp.com/pdf/SBIG/AOvsNoAO.jpg
The deviation between Paul's image and the theoretical performance limit of a 12" RC is of too great a magnitude to attribute to 1 - 10 Hz seeing variation... . period.

I might also point out that the star images in Paul's image are uniformly ellipsoid across the image. The blur circle has a long side (~130%) perfectly aligned to the Right Ascension axis... there's a clue...
Ergo, it aint an optical quality, field flattener, focus or seeing issue.



Two years without a properly focussed image?
Seriously?



You are invited to believe that unless you post a heap of pretty pictures on the internet, you cannot be possessed of the ability to analyse them.
Now the irony in this is that Paul has used similar language dismissing the comments of the only professional optician subscribed to this forum who has actually built a Ritchey Chretien.



To try and win an argument on the basis of being a self imposed authority figure isn't graceful, flavoured with condescension it is even less so.
But, when the argument is without substance.... well that is just pure comedy.

~c

[Paul Haese]

Got some facts wrong there Clive.

The camera is on a TSA which is mounted on top of the RC12. Hence the ellipsoid star images.

So its true and the rumour is correct, you do know everything.

[astroboy]

And people wonder why I got out of imaging .

[clive milne]

Ohh well, I was just quoting what you put down on your own web page:

http://paulhaese.net/NGC253.html

NGC 253

Image taken at Clayton Bay, South Australia

Equipment - GSO RC12 SBIG STL11002

Guiding - QSI OAG and Orion Star Shoot Autoguider.

L R G B -65 35 35 35 (5 minute sub exposures)

Darks, flats and biases applied

Processed in CCD stack and Photoshop CS6

[Paul Haese]

Clive if you read the line above it indicates that the RC12 has a STL11 on it. Guiding is through a QSI OAG. How does a QSI OAG go onto a STL11? :rofl:If you knew about imaging you would know what each of these pieces of equipment are. BTW where are your images?

Look this thread is really about the new RC16 and it is clear you and Mark have some beef against these RC scopes or feel the need to have a go at them. So why bother to hijack the thread? It completely disrupts the thread and puts off people who are interested in buying one of these scopes. Why not just let us discuss the scopes?