NGC7331 Image Artifacts

[Chris996]

Hi,

Could anyone give me any pointers on why I'm getting the large scale and small scale noise in this image (& how to improve it)?

Cant seem to remove either sufficiently well with DBE.

Any help / tips on what to look into really appreciated - I've been following the pixinsight tutorials for RGB pre-processing (inc. subframe selection and drizzle integ etc).

I've attached RGB combination & zoom plus the small-scale noise shown in green integration.  I'm imaging with a Atik Horizon Mono, LRGB filters, Bortle 6 zone

Cheers

Edited August 10, 2020 by Chris996

[geordie85]

Do you dither during your imaging sessions?

[vlaiv]

This is rather interesting as it is first time I'm seeing walking noise in action thanks to your animated gif!

Couple of questions:

1. Is camera cooled and if so - was it cooled at the time?

2. Did you take calibration frames for it and are images above calibrated?

3. Do you guide?

Interestingly enough - direction of noise walk is not either RA nor DEC but rather combination of the two - which is strange. Is there particular direction of the drift between first and last frame you took? Do they all move in same direction (small shift between exposures)?

In fact, could you do a animated gif like one you did, but this time using all the frames in order they were recorded (for one channel - green or the one you choose)?

There is big difference in background intensity in the gif - can you explain that? Is there a light source that goes on and off randomly or could it be high altitude clouds passing?

[michael8554]

Wow, I'd expect much better noise performance than that for £1600.

Walking Noise

Dither

Michael

[ollypenrice]

10 hours ago, michael8554 said:

Wow, I'd expect much better noise performance than that for £1600.

Walking Noise

Dither

Michael

And you'd be right. Something is not well here. Was the cooler active?

Olly