Is this a type of noise from DSLR?

[Baskevo]

Hi guys,

So I've been trying to process DSLR images in PI, and after stacking I keep getting this weird red noise-type structures... Here's an example:

Is that a type of noise? Is that caused from my stacking process, or light pollution, or is it from my sensor getting hot, or maybe from my darks being a different temp than my lights?

This is with over 120 subs, 120sec at 800 ISO. I took 50 darks, bias, and flat frames. I also created a super bias in PI. I dither every 2nd frame. I am also using an Orion Skyglow filter. I have tried fixing it with noise reduction, but the red does not go away.

Any suggestions on how I can fix this? Let me know if you need anymore info. As always, I really appreciate any help! Thank you!

[fatboy1271]

Hey James,

I'm curious what replies you get back on this. Nice round stars!

[OhNo]

That's the area between M110 and M31 isn't it?

[UlteriorModem]

There is a lot of 'typical' small scale noise in there as well as some large scale blotches. Is this a crop? How about you provide us with the entire image. OnNo may be on to something, that 'noise' might be actual 'structure' or filimants / dust lanes.

I ran the image through astrometry.net and it is indeed close to M110.

[Baskevo]

Here is a screen shot of the full image, I hope that is okay:

It is very muddy. It does get a little better if I run SCNR to remove the green first, and then do background neutralization afterward, but its still pretty muddy:

in both of the shots, I did a crop, DBE, photometric color calibration, and then SNR and background neutralization in the second image. It is with a stock DSLR. Could I be doing DBE wrong or something?
Obviously I don't have the best equipment nor am I shooting in the best conditions (bortle 8 at least), but I was just wondering if this is normal with a stock DSLR, and if there's anything I can do to fix it?

[OhNo]

I am no expert but I'd say it's light pollution. Remedy: move to a dark location!

[Baskevo]

Lol So any suggestions on how to fix it in processing?

Edit: I've been doing some reading on structural noise, and found some people saying that you should stay at ISO1600 b/c 800 is too noisy?? I thought it was the other way around! I shot this at 800, and I didn't see this problem when shooting at 1600 (I just couldn't shoot as long)

[Baskevo]

So I actually think this was from my stacking process! Thank god.

I ran a different set of images through DSS, instead of using lightvortexastronomy.com's pixinsight stacking process, and I got WAY better results.

I know it's a different target, but it's shot at same settings, ISO, and same night, but with less integration time:

I know it's still very noisy, but it's way better as far as the weird chrominance-like noise in the m31 stack above. All I did to this image was dynamic crop, DBE, background neutralization, and color calibration. It came out way better.

Has anyone who has used light vortex process had this problem? I'm going to try running m31 through DSS to make sure I get the same result.

[yobbo89]

something looks wrong. it's even over the data in the bright regions and the center of m31, it looks like some sort of stacking artifact.

you can see the m31 image has clumps of red and green, while your reprocessed/ restack of m42 shows the more common/normal noise of speckles of rgb.

[Baskevo]

It was definitely my stacking process! I stacked the exact same frames through DSS, and got a WAY better result!

This is only an auto-stretched, stacked image, without any further processing:

for the DSS images, I stacked them on my laptop with a SSD, which was a LOT faster than on my desktop, but I don't have a lot of storage on my school laptop.

I like that pixinsight gives you much more control over the stacking process (even though I essentially follow the same steps every time with the same result), and I would like to learn more from it. I was not using the batch processing script, so maybe I will try that next time I have a free 4 hours free lol but if anyone has any insight for why my images get so muddy from stacking in Pixinsight, it would be very helpful!