Can you point to any websites of people doing long focal length work with Newtonians ? The first remotely decent shot I ever saw taken with an 8" F8 RC was when Peter Ward put the tube on his Paramount.
Mark
Like I said I have not seen any really. Maybe just the odd one.
So you don't consider the images I did long before Peter as remotely decent? You must have seen these below. Or do you only look at images produced in NSW?
Would a televue powermate make a big difference with coma instead of a barlow?
Yes, the performance with a quality Barlow design will be very similar to native F ratio. Powermate design aren't technically a barlow lens although they do double the magnification .
There are high end Barlows designed for very fast scopes with no vignetting such as this :
At the time Peter posted his Omega Cen pic If I remember from a _very long_ thread , all the 'tyre kickers' had fallen asleep waiting for you guys to sort out your drooping focussers , and the pictures I saw up until then were very average I certainly don't recall seeing anything decent up until that time .
Nice pics. Congratulations . There is nothing at least in theory that suggests that Newts can't work just as well with an amplifier lens . I suspect its due to the implemetation more than anything else. A cheap Barlow lens is not going to do the job.
Mark
Quote:
Originally Posted by Paul Haese
Like I said I have not seen any really. Maybe just the odd one.
So you don't consider the images I did long before Peter as remotely decent? You must have seen these below. Or do you only look at images produced in NSW?
If you are considering purchasing a GSO RC and have reservations regarding the quality of the focuser, bear the following in mind:
Your imaging requirements can be SIGNIFICANTLY different to the next persons. Do you intend to only connect a DSLR and use a separate guidescope, or are you putting on an imaging train consisting of an adaptive optics off-axis guider, large capacity filter-wheel and a heavy large-format camera (800g vs 5kg or greater). The market for these scopes is comprised of people just starting out with DSLR's (or even guide-cameras) to pretty sophisticated setups.
If all I was going to use was a 800g DSLR (Canon 450D), I would be turned off the purchase if I had to pay for the top-end quality focuser that would be required for the heavy imaging trains some guys use. Where do you draw the line? Focuser good enough for 1kg, 2kg, 3kg, 4kg, 5kg.... It makes perfect sense for the manufacturer to cater for the lowest common denominator, then give the user the choice of their own focuser that is ideally suited to their own needs. So the real question is: is the stock focuser good enough for a DSLR with nothing else?
I would be quite happy if they sold the scope without a focuser - but what do you do when it is delivered and the preferred focuser is still being shipped? No playing then with the new toy....
You target the market supply cheaper focuser sell more scopes then leave it up too the end user to choose their own knowing that in reality this is what happens anyway.
One should remember these are mass produced consumer items. one size fits all
Some might like Feathertouch, others have a preference for Moonlite, JMI or Robofocus and even Toadloaders
I've seen really good images from inexpensive set ups and vice versa.
I think we make too much out of what is better APO vs RC v Newtonian vs Mak
At the end of the day it doesn't really matter what you've got it's how you use it.
In fact I can see myself in years too come with possibly one of each.
To start off topic:
When those new 8"RC owners contacted the seller about the initial issues; did you guys ever get a reply or resolve?
Sounds to me like GSO have serious QA problems if these scopes are being sold with design flaws, collimation out of whack, optics problems.
I'd be sending strong questions to the manufacturer and wanting a warranty replacement or money back.
People are complaining about collimation out of the box; and focuser issues? Isn't this the norm with any Cass, CDK, RC type scope? Be prepared to collimate and adjust the optics yourself unless you send it back to be 'serviced'.
This is a poor-mans RC no? GSO focusers aren't exactly superior..
Seems like everyone is expecting this scope to be similar to a scope over $5000 for some reason.
Same could be said for the CDK type design of the VC200L. An excellent performer; but lacking with spider vane design and poor focuser system.
Both can be upgraded to improve the scope dramatically.
leinad, I was pretty much in contact with Jim Sheng within hours of sending him my initial impressions. He was quick to respond. When I did my review of the scope and posted it on the internet items were fixed on the following batches. The unfortunate part is that the new baffle will not fit the older scopes so I had to make do with what I had and worked on flocking the baffle myself.
I think that the scope really needs to be another 4 or 5 inches longer to prevent dewing problems.
If you are considering purchasing a GSO RC and have reservations regarding the quality of the focuser, bear the following in mind:
Your imaging requirements can be SIGNIFICANTLY different to the next persons.
Exactly, sheesh, so much grief. A carbon fiber RC for some $1800, thats insane . You pay for what you get, in this case not a lot (the price), so what you need to replace the focuser and deal with some short falls, get over it, you lot are not are not so nieve to think you get the *lot* for that price?, despite the advertising. If you want the lot, pay too much for an RCOS (the TCC alone is a whole different world) and be done with it.
Seems to me, GSO RCs are are very good deal indeed, so long as you accept some fiddling maybe required. Im amused by ppl who think the world owes them the ultimate quality product regardless of price, and ignore simple common sense.
Thanks for all the information everyone. From my original question I was hoping to find out if anyone that had actually purchased one of these scopes and if they could give me a lead on how they operated. I have read and heard a lot about the 8" GSO RCs.
From what I can gather the 10" GSO RCs have very good optics, not very good focuser and don't weigh an enormous amount. Although I have not been able to find out how much they weigh. Somewhere between 12 and 15kilos I believe? I don't have any idea whether they are easily balanced or how much back play is required to gain focus when imaging. I am assuming that it would be quite a bit. Maybe up to 300mm.
I was expecting to buy a new focuser anyway. I bought a Moonlight for my ED127.
If the optics are good then the main battle is won.
Interesting discussion
As a beginner imager i looked at these scopes two, but waited to see what they would be like.
They can certainly take wonderful images, but that is to be expected as they are a scope designed mainly for imaging not visual.
What I don't like is that it took a person to buy one before obvious design defects were addressed.
So did they actually do "serious Q&A" or we tested it some that will do ?
Baffles that don't work properly and a focuser that droops on light imaging gear ?
Enough said on their quality testing, they have brought RC's to the average imager if u want one which i'm glad of as i will probably get one two, but i'm waiting to see what faults the 10"will bring before i consider spending my hard earned cash.
Also a G11 should handle this scope ok for imaging yes ? ( just a short side track )
Oh to win lotto
That is because a Newtonian is not as sharp as an RC (my opinion and certainly many others) and a fast Newtonian is not always the answer Mark. Tools for the job.
Well, here's the 100% crop of the area in Eta Carinae done with a Newtonian (not very good example but that is the only image that I can directly compare now with those you offered).
To my (old!) eyes, detail in it is even sharper than on one you offer on your site. Note some tiny Bok globule, those black 'dots', completely absent in your image - can you give us 100% crop as well ?
I have clocked some globulars with 2.2 arc second FWHM, that is my best to date (and that is always going to be SEEING limited, with better seeing I could certainly do even better). What FWHM (long term) do you get with your RC ?
At the time Peter posted his Omega Cen pic If I remember from a _very long_ thread , all the 'tyre kickers' had fallen asleep waiting for you guys to sort out your drooping focussers , and the pictures I saw up until then were very average I certainly don't recall seeing anything decent up until that time .
Happy to volunteer this pic of the same (heavily jpeg compressed to scrape under attachment rules) done with a humble Newtonian ...
Bratislav, here is a crop of my image on my site and I think mine is sharper, might be time for a new prescription . There arn't any bok globules where you are looking. I think you are looking at dust on the sensor.
BTW I agree with Bassnut all the way. Well put Fred
There arn't any bok globules where you are looking. I think you are looking at dust on the sensor.
I think you're right. It might be dust. Here's a HST crop of the area.
Although your picture in this case is much sharper than a newt I agree that a well collimated newt can be on par with those GSO RCs.
Bratislav, here is a crop of my image on my site and I think mine is sharper, might be time for a new prescription . There arn't any bok globules where you are looking. I think you are looking at dust on the sensor.
I stand by my comment, it was not a very good example
But armwaving notwithstanding, FWHM is easily obtained single number that can be compared without any squinting at the screen. As I said, I now routinely get into 2.5 arcseconds with occassional excursion towards 2" flat. I don't think any RC would do any better with same seeing conditions. I'll post some 100% crops of those sessions later.
And BTW if you think GSO RCs are such a good value at 2.5K (or whatever you ended up paying after all of the mods), consider that my Newtonian has whopping 200$ invested into it !
