M83 - 12hr DSLR send off

[assbutt94]

A few months back I set the goal of 12 hrs on M83. This may well be the 5D's final proper go at deep sky.

I've done a quick rough stack using DSS, 168 frames, 12hr 55mn exposure time.
Subs are over various nights at different moon phases, exposures and yadda yadda.
Darks, Flats and Bias are used.
I've spent well over 24hrs editing the stack as practice. I want to cull the data more selectively with pixinsight and try a 3rd edit, but I dont feel I'm doing the data justice so far as it is.

It seems very noisy? Am I expecting too much from the camera or am I probably making a mistake in the editing process?

https://www.astrobin.com/vejd8q/

[xelasnave]

Great image, Pixinsite must have something to manage the noise I know Startools removes noise rather dramatically.
However looks great to me.
Alex

[RyanJones]

Absolutely love this rendition Nathan. The colours are fantastic. As far as the noise goes, I use an old entry level DSLR which is inherently incredibly noisy so along the way I’ve learned how to at least polish it up in the background. This is a process that is very selective and takes a while to get right. I still don’t believe I’m 100% there but given my data I’m pretty happy with it. My processing is done in photoshop though so I can’t give you a walk though.

Again, congrats on a cracking image. Well done.

Cheers

Ryan

[Startrek (Martin)]

Well done , that’s a really nice M83 , plenty of detail there and love the colour
You spent some long hard hours on this one but there is a point of diminishing returns when it comes to stacking huge amounts of data and expecting a high SNR in return ( especially with noisy DSLR’s )
The point of diminished returns on my Canon 600D is about 4 hours of data no matter how good the subs are, adding an extra hour or two just increases the noise for no gain in detail
I only use Startools for post processing which is probably one of the best programs for mitigating noise in your images, but like everyone keeps saying a DSLR can only do so much , but hey they still do a great job considering their limitations and are simple to use

[Sunfish (Ray)]

Looks good to me. A little luminance noise reduction in Lightroom would maybe help but the detail is there as it is .

[ChrisV (Chris)]

+1. That's a really nice image. Excellent detail without overblown colour.

[LostInSp_ce]

Nathan you have a great image of M83 the background noise is a little high but it can be removed. I don't know what the processes are in PixInsight but the fundamentals should be the same. When removing noise it's sometimes better to do a pass on each channel rather than on all three. Do you use masks to isolate star and DSO data? They help protect the good signal from the bad. Personally I think it's fine to have some background noise in an image because it looks more natural. Especially when it's a DSLR image as it's a characteristic of the technology, just like film grain is to SLR. I too like Martin find about 4-8 hours of data to be the sweet spot depending on sky quality temperature e.t.c. so I wouldn't go to crazy on the exposure time with a DSLR.

[assbutt94]

Thankyou Alex. Pix-insight has plenty of Noise reduction tools, and I've used them in the past with I feel, better success. Startools has an interesting (and unique?) approach to noise reduction.

Thanks Ryan, I also use noise reduction tools selectively. It definitely takes a while to tweak and get right.

Cheers Martin! From what I read a while back, basically every 4x number exposures = 0.5x noise. Pretty sure that was from "The Deep Sky Imaging Primer". Great book, by the way. Absolutely, they do well enough to get many people hooked on the hobby!

Thanks Ray, I sometimes apply NR to luminance only, in pixinsight.

Cheers Chris! I try not to over-do it

Thanks LostinSp_ce! I use inverted luminescence masks that have been stretched to better protect the galaxy/details and to increase NR strength on the background, and leaving only very light NR on the darkest dust lanes. Sometimes I blur the mask a little. Sometimes I just use a range mask.
I've applied NR to the Luminance layer as well as RGB layers but I haven't tried individual RGB channels. I'll definitely have a go at that.
I do use "SCNR" though, which applies only to the green channel as I find this to be the worst culprit for noise (at least to my eyes). I absolutely agree with you when it comes to having some background noise to keep it looking "natural". My personal goal is to just smooth it out a little so there is no obvious dots/pixels that stand out too much.


I've now down-sampled my image to original image scale at the end of my edit and this has also helped. I normally do this but I cropped a lot of my Stacked image out to include more subs so didn't feel the need to downsize originally

You guys have convinced me to definitely do a third edit, and cull the data down. I'll pick out my best exposures and maybe I'll even be able to tease out some more details.

Thanks guys for the thoughts!

[assbutt94]

Just an update, I've culled the data down to about 76 exposures by excluding subs with outliers in FWHM, eccentricity, SNR values, and cosmetic flaws.
After a week or so, and a few more iterations of editing, I definitely see an increase in detail compared to my original stack of exposures, through the whole process.

This is the latest iteration, but I think it's a bit overcooked.
https://www.astrobin.com/vejd8q/C/

I'll be going back to the stack after I stretched it to try another iteration. Maybe a little less reds, I was aiming for something between both my newer and older photo. Maybe a bit more yellow in the center bar, like some images hubble has taken.

[assbutt94]

Another take, basically started from the non linear stretch and went from there.
Its a but less processed, background and stars have been masked better. Toned back HDRmt and LHE.
Missed the mark again with colours but i might try touch that up a bit more later.
https://www.astrobin.com/vejd8q/D/
Any critiques and opinions are welcome, I've a feeling ill be having another go

[assbutt94]

I've played around a bit more. Messed with the curves a bit, bit of noise reduction, adjusted the black point. Sharpening and saturation. Stuffed around with a few dozen masks trying to tune each step for a better result.

I think this is the final edit. A better person might get more out of my data, but im happy with the result and feel like ive done good enough justice for my camera

I also counted the exposure times of my exposures and updated the astrobin info to make it more accurate.

https://www.astrobin.com/vejd8q/F/

Thanks again for the comments and thoughts!

[LostInSp_ce]

I like it Nathan, you've been able to suppress the background noise for a smoother result and the colour adjustment has given it a little more warmth. Good work.