May i ask, only if you have spare time - what is the difference between the drizzled and non-drizzled version? could you post or pm a non-D'd version? I'm asking as I'm expecting delivery of a Sony A7s astro modded camera soon, and am worried that its large pixels (8.4nm) may mean that I'll also need to drizzle, but am unsure as to how small the issue will be (eg the tiniest stars frankly won't matter imho...)
Very kind of you Fred, being one of the masters of high wow factor
Quote:
Originally Posted by SimmoW
Magnificent Rick.
May i ask, only if you have spare time - what is the difference between the drizzled and non-drizzled version? could you post or pm a non-D'd version? I'm asking as I'm expecting delivery of a Sony A7s astro modded camera soon, and am worried that its large pixels (8.4nm) may mean that I'll also need to drizzle, but am unsure as to how small the issue will be (eg the tiniest stars frankly won't matter imho...)
Your work is most inspirational.
Thanks, Simon.
I have attached a crop of the original Drizzled image and a downsampled version which is at the original resolution. This is cheating a little but close to what you'd see from a non-Drizzle version (in reality the non-Drizzle version would be slightly inferior with stars a little more square.)
Drizzle is only useful when the scope/camera combination is significantly undersampled. At SRO the seeing is exceptional, often down near 1 arcsecond so this is easy to achieve with our image scale which is around 2 arcsec/pixel. TANSTAAFL, of course, and Drizzle does trade off noise for resolution so you need more data too.
What focal length will you be using with the Sony?
BTW, someone told me that the small area of dark neb looks like a bear
Er, I can't discern much difference. Which is probably good, 2 arc secs/pixel is probably well within tolerances - I've read that 3-4 is the limit.
I'll be using it with my Tak E-130D, 430mm FL, meaning that it'll be more like 4 arc secs/pixel.
Thankfully I've found an example image taken at a similar FL, here, that proves to me that the issue is certainly not worrisome to me. I detect some squareness if zoomed to the very smallest stars, so drizzle might be of use, but you really do have to zoom in close. Compared to the ridiculous sensitivity of the cam, I don't really care.
Hope I'm not hijacking your thread, but as you mentioned drizzle, it pricked my attention.
Er, I can't discern much difference. Which is probably good, 2 arc secs/pixel is probably well within tolerances - I've read that 3-4 is the limit.
I'll be using it with my Tak E-130D, 430mm FL, meaning that it'll be more like 4 arc secs/pixel.
Thankfully I've found an example image taken at a similar FL, here, that proves to me that the issue is certainly not worrisome to me. I detect some squareness if zoomed to the very smallest stars, so drizzle might be of use, but you really do have to zoom in close. Compared to the ridiculous sensitivity of the cam, I don't really care.
Hope I'm not hijacking your thread, but as you mentioned drizzle, it pricked my attention.
The difference is fairly subtle, Simon, except for the shape of the stars. I did a quick non-Drizzle integration of the Ha and attached to this post is a direct comparison of Drizzled Ha vs non-Drizzled with no processing apart from an equivalent stretch and upsampling.
Brilliant Mr Rickster, - crypeeze, oversampled, undersampled, the only undersampling done here is with Rum & Coke
Man, what I really like abouth <- (oops, stop slurpin ) this image Rick, is the sharpness around most the field, and Im also seeing some blurred section around low middle and bit to left where blue meets dark - how facinating is that - it appears like you have captured some serious intersteller turmoil winds or somethin' ?
Cheers for any insight master
Another excellent image Rick, love the colour's.
Erik
Thanks, Erik.
Quote:
Originally Posted by astronobob
Brilliant Mr Rickster, - crypeeze, oversampled, undersampled, the only undersampling done here is with Rum & Coke
Man, what I really like abouth <- (oops, stop slurpin ) this image Rick, is the sharpness around most the field, and Im also seeing some blurred section around low middle and bit to left where blue meets dark - how facinating is that - it appears like you have captured some serious intersteller turmoil winds or somethin' ?
Cheers for any insight master
Ta, Bob. What's happening here is that the radiation and stellar winds from a cluster of stars has carved out huge caverns in the dust. You'll notice pillars where denser material has eroded more slowly. Where the dust is compressed new stars are forming. So, you're right about the turmoil and interstellar winds
Not that exact one Rick, but yeah, they are super grouse !
Wondering if he does them for other astro-imagers, you know, really good astro imagers That would be quite
Lovely colours, this one always reminds me of a Buffalo or Bison. S2 edges aginst OIII look very strong and pleasing.
John.
Thanks, John. I've heard it called the Embryo Nebula but Bison would be a good fit too!
Quote:
Originally Posted by astronobob
Not that exact one Rick, but yeah, they are super grouse !
Wondering if he does them for other astro-imagers, you know, really good astro imagers That would be quite
I think he's probably busy with his own stuff. I wouldn't mind trying the 3D stuff one day but I have about 20 images to process first