M106 & some faint fuzzies

[Aramcheck]

From last Wednesday night... 51 x 180sec subs. SW200dps + EQ6 + Cannon 600D (astromodified) & IDAS D2 light pollution filter... Bortle 6 skies. Second night guiding & haven't got dithering working yet...

Thanks to @wimvb & @discardedastro for the tips on processing in Pixinsight!

Cheers
Ivor

[MarkAR]

Lovely image.

Still has a slight colour tint to the background. Wonder if masking and hitting it with SCNR might work.

[Annehouw]

The image is nice!

I also see the gradient.

You could go for another round of ABE or DBE, followed by SNCR and a new color calibration (PCC would work well, I think).

[wimvb]

You have can safely use DBE in the non linear stage. Just check the normalize box in the corrections section. This keeps the median value of each channel and you don't need to redo colour calibration then.

A neutral background can still appear to have a colour cast. This is a result of one channel being more noisy than the others. The histogram peaks of the channels coincide (neutrality) but the noise increases the number of bright pixels in one channel (wider histogram), making it look like you have a colour cast. The proper remedy is (chroma) noise reduction. Desaturation at the end of the workflow also works.

Edited May 16, 2020 by wimvb

[Aramcheck]

On my PC the gradient doesn't isn't as noticeable from within Pixinsight, but following @wimvb's advice I redid DBE on the v2 image and that has helped a great deal.

Cheers
Ivor

[MarkAR]

Hell of an improvement.

[ollypenrice]

Yes, much better. I don't know how you'd do this in Pixinsight but in Photoshop I'd select just the background sky, reduce the colour saturation and run the noise filter to reduce colour noise. The background is still quite 'colour busy' but it's a cracking image. Did you try a light dose of SCNR Green?

Olly

[wimvb]

1 hour ago, ollypenrice said:

I don't know how you'd do this in Pixinsight but in Photoshop I'd select just the background sky, reduce the colour saturation and run the noise filter to reduce colour noise

Selecting areas in PS is equivalent to using a mask in PI. In this case a lightness mask, probably contrast enhanced.

Reduce colour saturation is the same in PI.

Reduce colour noise is using any of the noise reduction tools in PI in Lab mode on chrominance.

I tend to use colour noise reduction early on in a process, and colour desaturation in the very end.