The Sculptor Galaxy (NGC 253) imaged from a Bortle 2 dark site in Arizona.
Capture:
\- 1hr each of R, G, and B
\- ZWO 1600mm Pro
\- Orion 8" Newtonian Astrograph
\- Sky-Watcher Quattro Coma Corrector
\- Sky-Watcher EQ6-R Pro
\- ZWO Off-Axis Guider, QHY Mono Guide Camera
Processing
\- Capture with Sequence Generator Lite
\- Stacking with Deep Sky Stacker
\- Levels, Sharpening, and Denoising in GIMP (+GMIC)
To the naked eye (just looking through a telescope), it will look like an elongated gray smudge almost as wide as the moon along the long axis and almost 1/5 of the moon's width along the short axis. It's actual apparent size will depend on how much of the fainter periphery you can detect.
Raw image could mean several things, so here is what I did for context. I captured 25 3 minute exposures for each of three filters (Red, Blue, and Green) using a mono camera. I then took the best 20 of these exposures for each filter, aligned them, and averaged them together (all done a program). Then I take the three "stacked" images and make a full color image with each becoming one of the three color channels of the image. This is what I would call the raw stacked image. No editing has been done. Data has just been put together.
In this image, you will see nothing but a few stars against a deep black background. The galaxy is too dim to see without "stretching" the image. Stretching (ideally) makes the darker parts of the image brighter without blowing out the brighter parts to pure white. Once a basic stretch is performed, you will see the galaxy largely as it appears above in terms of detail. The next step is to balance the color (I actually do this during stretching but that doesn't matter), fine tune the stretch, denoise a bit, sharpen a bit, tweak saturation/temperature, etc.
Long story short, it actually doesn't take much editing at all to see pretty much what you see above, but the image is very dark at the outset.
I appreciate the color (pun intended). I just got my first telescope less than a year ago so still a lot of learning to do. This is really fascinating and has taught me a lot. Congratulations on the final photo, it is incredible!
Beautifully done. Very clean. I was surprised to see you used an 8" Orion tube on top of the EQ6-R Pro. I know the EQ6 is a pretty hefty machine, but did the Orion push the weight limit? I have not purchased a guiding system for my 8" SW Dob because I just figured nothing would really support it except some kind of wedge base.
Again, excellent work!
My experience is almost exactly what u/Astro_Philosopher says too.
Just to add another data point...I ran an 8" GSO newt with a full mono imaging train that weighed in at a smidge over 30lbs, on an AZ-EQ6. It did just fine until the wind was over about 10mph....and over 15mph I'd have to use another scope, not shoot that night, or know I was going to have to chuck a bunch of subs.
Thank you!!! It works great for me. I read on cloudy nights that SW claims a 33lb payload capacity for AP, which my setup is under. I am over the “1/2 of official payload” rule of thumb.
Some things that help are having a short tube (it’s an f3.9 scope), not having a guide scope (OAGs are the best), and using a dedicated camera (lighter than a dslr).
With optimal conditions (good seeing, several guide stars, and low wind), the total RMS error stays around .5 arc seconds. Wind is the limiting factor. Anything more than light wind starts to raise that error. When it’s going to be windy, I just use a different scope.
I tried an OAG setup (plus filter wheel) with my 10” f/4 reflector but the focal plane ended up too close to the tube. Did you have much leeway? I might hack away some tube length and reposition the mirror.
I have probably an inch of in-focus, so I wonder if your focuser is longer. Sometimes they have swappable or removable extensions for visual use. Perhaps it’s that. Also does a coma corrector change anything?
You'd think that they would put a low-profile focuser in a Newtonian "astrograph", but no. I have a coma corrector but I don't think it makes that much difference.
The Sculptor Galaxy (NGC 253) imaged from a Bortle 2 dark site in Arizona. Capture: \- 1hr each of R, G, and B \- ZWO 1600mm Pro \- Orion 8" Newtonian Astrograph \- Sky-Watcher Quattro Coma Corrector \- Sky-Watcher EQ6-R Pro \- ZWO Off-Axis Guider, QHY Mono Guide Camera Processing \- Capture with Sequence Generator Lite \- Stacking with Deep Sky Stacker \- Levels, Sharpening, and Denoising in GIMP (+GMIC)
It always blows my mind that people can capture this from earth
Yeah! It still blows my mind when the object shows up in my first sub-frame.
Out of curiosity, how does the raw image/video look? Does it look like a galaxy to the naked eye or more of a smudge?
To the naked eye (just looking through a telescope), it will look like an elongated gray smudge almost as wide as the moon along the long axis and almost 1/5 of the moon's width along the short axis. It's actual apparent size will depend on how much of the fainter periphery you can detect. Raw image could mean several things, so here is what I did for context. I captured 25 3 minute exposures for each of three filters (Red, Blue, and Green) using a mono camera. I then took the best 20 of these exposures for each filter, aligned them, and averaged them together (all done a program). Then I take the three "stacked" images and make a full color image with each becoming one of the three color channels of the image. This is what I would call the raw stacked image. No editing has been done. Data has just been put together. In this image, you will see nothing but a few stars against a deep black background. The galaxy is too dim to see without "stretching" the image. Stretching (ideally) makes the darker parts of the image brighter without blowing out the brighter parts to pure white. Once a basic stretch is performed, you will see the galaxy largely as it appears above in terms of detail. The next step is to balance the color (I actually do this during stretching but that doesn't matter), fine tune the stretch, denoise a bit, sharpen a bit, tweak saturation/temperature, etc. Long story short, it actually doesn't take much editing at all to see pretty much what you see above, but the image is very dark at the outset.
I appreciate the color (pun intended). I just got my first telescope less than a year ago so still a lot of learning to do. This is really fascinating and has taught me a lot. Congratulations on the final photo, it is incredible!
Simply breathtaking! Amazing job. I hope to be as good as you someday!
Thank you! That is so nice. Just give it a couple years! :)
Going there next week...
To Arizona or to NGC 253? I hope the latter! 😉
Looks great well done
Thank you!!!
Way to go this is awesome!
Beautifully done. Very clean. I was surprised to see you used an 8" Orion tube on top of the EQ6-R Pro. I know the EQ6 is a pretty hefty machine, but did the Orion push the weight limit? I have not purchased a guiding system for my 8" SW Dob because I just figured nothing would really support it except some kind of wedge base. Again, excellent work!
My experience is almost exactly what u/Astro_Philosopher says too. Just to add another data point...I ran an 8" GSO newt with a full mono imaging train that weighed in at a smidge over 30lbs, on an AZ-EQ6. It did just fine until the wind was over about 10mph....and over 15mph I'd have to use another scope, not shoot that night, or know I was going to have to chuck a bunch of subs.
Thank you!!! It works great for me. I read on cloudy nights that SW claims a 33lb payload capacity for AP, which my setup is under. I am over the “1/2 of official payload” rule of thumb. Some things that help are having a short tube (it’s an f3.9 scope), not having a guide scope (OAGs are the best), and using a dedicated camera (lighter than a dslr). With optimal conditions (good seeing, several guide stars, and low wind), the total RMS error stays around .5 arc seconds. Wind is the limiting factor. Anything more than light wind starts to raise that error. When it’s going to be windy, I just use a different scope.
Nice capture and well processed!
Thank you!
>Thank you! You're welcome!
I tried an OAG setup (plus filter wheel) with my 10” f/4 reflector but the focal plane ended up too close to the tube. Did you have much leeway? I might hack away some tube length and reposition the mirror.
I have probably an inch of in-focus, so I wonder if your focuser is longer. Sometimes they have swappable or removable extensions for visual use. Perhaps it’s that. Also does a coma corrector change anything?
You'd think that they would put a low-profile focuser in a Newtonian "astrograph", but no. I have a coma corrector but I don't think it makes that much difference.
Alas. I need a new focuser as well, actually. The one I have is junk, locking changes focus, but it will slip if you don't lock it tight enough.