Here's the (again heavily reduced and compressed jpeg) of NGC104 done with a Newtonian. Measured FWHM on raw subs was around 2.2 arcseconds for that shot (combined exposure around 40 minutes). Second image is 100% crop.
Here's the (again heavily reduced and compressed jpeg) of NGC104 done with a Newtonian. Measured FWHM on raw subs was around 2.2 arcseconds for that shot (combined exposure around 40 minutes). Second image is 100% crop.
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.
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....
This is a very pertinent comment. The demands on equipment vary dramatically and I would think the obvious solution is to ship the unit without a focuser altogether. The comments I see indicate that the focusers being shipped are sub-standard and will only end up rotting some place. Thats a waste of money and materials.
Having said that, you would think that someone buying an decent R.C. had imaging in mind and the manufacturers would be wise to build a back plate capable of supporting whatever imaging flatform may be required, with a standard rear cell thread yes? Likewise, anyone spending bucks on a decent OTA is likely to have a specific imaging goal, and hence focuser in mind...
Not to sound like a downer on good times here, but how did we get onto Newtonians Vs RC's in the quest to answer the question "Any feedback on the GSO 10" RC?"
Each to their own boys... There are things you can do with a newt that you wouldnt bother doing with a newt, there are things you can do with a newt that you couldnt do with an RC too... Simple answer, buy both...
Showing images of Target X from one scope, with a specific camera, taken in certain conditions and comparing them to images from a different scope and camera setup in different operating conditions of a different target is a really really big waste of time..
Not to sound like a downer on good times here, but how did we get onto Newtonians Vs RC's in the quest to answer the question "Any feedback on the GSO 10" RC?"
Paul H. posted that RC's were intrinsically 'sharper' than Newtonians (!) . I couldn't let that one through to the keeper Sorry to have taken this thread off topic .
On the focuser subject, I have an 8"RC with the newer focuser as delivered. This is an upgrade to the one Paul has. I have still changed mine over to a Moonlite, but mainly because I hang a lot of weight off it. I believe that for most people, without the massive rig I've got, the standard GSO focuser would be easily good enough to do the job.
So unless you've got the several kgs of stuff hanging out the back of your RC, I wouldn't bother with the focuser upgrade. The 10" focuser looks even better than the one I have.
Here's a pic of mine waiting for the clouds to go away!
Here's a shot I did of 47Tuc, FWHM of about 2.5", this was with the original focuser and the scope as it was delivered. It needed a bit of a tweak of the collimation.
<Off topic>
The camera used was QHY8, at approx 1.1 arc sec per pixel scale.
And sorry Alex, comparing best FWHM is not waste of time, but the only way to objectively compare (debunk?) the resolution abilities of certain configurations.
Stuart, was 47 Tuc shot with AO unit ?
</Off topic>
Comparing FWHM isn't all that useful, your local seeing conditions impact on FWHM. More often than not, your seeing conditions will be a lot worse than the resolution provided by your telescope... Also longer focal length scopes will almost always give higher FWHM's than a short F/L system given identical seeing conditions... Just an observation I've made when testing two different optical systems side by side..
Don't take it the wrong way mate.. I'm more a newtonian fan than an RC fan... And agree with much of what you and Mark have said, Its just your method of proving your point seems flawed to me.
Fact of the matter is you're comparing two very different optical systems, in different seeing, with different mounts, different cameras... Trying to get an idea of which scope produces better star images. There is no standardization in your comparisons, so they aren't definitive proof of either systems superiority..
Both optical systems are producing great images for their owners... That should be good enough for everyone..
<Off topic>
The camera used was QHY8, at approx 1.1 arc sec per pixel scale.
And sorry Alex, comparing best FWHM is not waste of time, but the only way to objectively compare (debunk?) the resolution abilities of certain configurations.
Stuart, was 47 Tuc shot with AO unit ?
</Off topic>
Yes it certainly was using the AOL. This reduces the amount of mount induced star bloating to almost zero, when it's properly used. Unfortunately the AOL doesn't react fast enough to counteract seeing induced star bloating.
Now the only way to positivley resolve (pun intended) this is to have a shootout. We need Bratislav, myself and someone with a big refractor, all around the same FL on one night and a bright target with a good guidestar, then swap my camera setup between the lot and see which scope is best. I also have a Meade 10"ACF OTA, which we can add into the shootout. We really would need a CDK as well, then we could call it a shootout at the DK corall.
Maybe we could use the LMDSS on a full moon, when it won't be being used...
Back on topic, I know someone with the 10" RC, we will be comparing notes soon, when we get together for a BBQ.
Well I guess that can be the backup plan in case we can't find one, but don't forget these claims.
Well I'm afraid closet you may get is 12.5".
What's the point in pointing at Planewave? We might as well be talking about RC Optical Systems as well. http://www.rcopticalsystems.com/
Why not.... This thread has gone every which way anyway.. Lets get a 12" F/9 LZOS triplet APO, a 12.5" RCOS, a 12" Astrophysics Mak-Cass, a 12.5" CDK and an ASA N12 Newt and see how they fare against the GSO 10" RC, VC200L, Skywatcher ED80 and GSO 8" newtonian, and SW 180 MC...
Should be a fun test.. Fair too... Oh hey, lets put them all on different mounts with different cameras under different quality skies too.. That way it should be a much better test to see which telescope is the best.
Sorry to have taken this thread off topic .
