NGC 1499 ft Walking Noise

[Iem1]

Hello darkness my old friend...  

WO Z73, Modded Canon 600D + Sky guider pro

Captured ~2 hours on the California nebula last night (x251 30 second subs), manually dithering between 90%-95% of the subs which has worked great the last few times, but not so much this time apparently. I was using the bright star at the top of the image and keeping it aligned to image info on my 600D's screen while dithering to ensure I did not move too much and make stacking harder, but I do not think I was moving enough this time.

I thought I did a great job, not bouncing the target around the FOV all night..

I tighten/loosen the dec screw and give the RA axis buttons a push on my Sky guider pro between images to dither between each frames, usually I move around a lot over the hours, makes stacking a little more complicated as I need to crop more, but the dithering really works. Lesson learned.

I also realised my uniform white light I use for flats was not so uniform anymore AFTER i took my flats, disassembled my setup and stacked my images. Big old gradient appeared, I checked the tracing pad and sure enough, one edge of the pad is dim.

Had to commit the ultimate astro sin and reassemble my gear, guestimate my focus and camera orientation to take some flats and hope they worked, which I think they did luckily!

Walking noise aside, this is where I am at with 2 hours...Was going to shoot for 4 hours, but not sure I will now with all that noise. Shame.

[Iem1]

Been reading up on walking noise and some people suggest that adding more data should help dilute the data set and decrease the walking noise?

If I were to try add 2 more hours data and dithered a bit more aggressively, do you think it will help break up the walking noise? Or is it just ingrained now from the first half of the data? 

Cheers guys

[ONIKKINEN]

I doubt i would have noticed or mentioned the walking noise as a problem if you didnt point it out, it looks great!

But yes more data should reduce noise nicely. Or binning, or both? The walking noise is really subtle and on its way out, i reckon 2 more hours will drown it out as long as there is enough dithering.

[alacant]

1 hour ago, Iem1 said:

up on walking noise

Hi

The noise is probably not walking noise, rather artefacts left over from the debayer. I've seen it before on DSS using simple bilinear. Convert to fits -I'd recommend: Siril- and try the super clean RCD debayer [1].

The idea of another 4 hours will certainly help eliminate the little noise/artefacts you have; your manual dither is working well.

Lovely shot. Excellent for just 2 hours.

[1] no one can find it. It's here:

Edited December 3, 2021 by alacant

[Iem1]

Thank you guys, il be sure to add more data! 

Though, it looks as though our recent stretch of clear night's has come to an end, might be a while before I can get back to work on it!

I will for sure try stacking in Siril, I was too lazy to convert files and make space etc so I chucked it into DSS just to see if the DIY flats were going to help