M78 Casper the friendly ghost

[Padraic M]

This is 2hrs of OSC RGB on M78. As an emission nebula it's ideal for OSC in dark skies, and an ideal size for my SW 150PDS/ASI533MC Pro combo.

NINA capture, APP and Siril processing.

The green channel is really clean, but both blue and red were quite noisy. Is this a feature of high humidity in the atmosphere? I excluded an extra 1 hour of lights as 99% humidity gradually became 100% cloud. Quality improved a little with less-but-better data and I could stretch more without highlighting the noise.

 

[Padraic M]

A reprocessing of this image, using GraXpert gradient removal tool.

Workflow is Stack all subs in APP -> linear stack into GraXpert -> linear output into Siril for stretching/median filter/stretching -> final touches in Gimp. I think this allowed more stretching for the same noise levels, and brings out more detail.