How can I edit a RAW night-sky photo to make stars stand out more like the camera JPEG?

Question

I shot a night-sky scene on a Sony A6000 in RAW+JPEG and noticed the in-camera JPEG shows more visible stars, a darker sky, and a better-looking foreground than my unedited RAW export. In Darktable, the RAW looks flatter and redder, and even after adjusting the base curve I still get fewer stars and a less neutral sky.

What edits are typically most effective for bringing out stars and making the sky darker and less red when processing a RAW astrophotography image? I'm especially interested in understanding why the camera JPEG can look better at first, and which controls in RAW processing are most useful for reproducing or improving on that look.

user75526 · Answer

Darkness of the Sky

I use RawTherapee because I cannot get darktable to do what I want. The first thing I notice is that the camera and darktable white balances are different. The luminance of the images are similar, but we perceive warmer colors as "brighter", so change white balance to auto. After that, it is a matter of playing with settings until you get what you want or something you can work with more in GIMP.

When I open the file in darktable, I get a message: "failed to read camera white balance information", which confirms my initial assessment. Since darktable does not have an auto white balance setting, you pretty much just have to try each option until you see something you like.

Shadow Details

(Back to RawTherapee...) To enhance shadow details, decrease the black level (to -1700 in this case) and increase shadow compression. It can also be helpful to increase exposure. There are other tools you can try, such as Shadows/Highlight or Tone Mapping.

Appearance of the Stars

To further enhance the appearance of the stars, try Local Contrast and Microcontrast.

Miscellaneous

You can make the usual adjustments to curves, lightness, contrast, saturation, etc. You can try a Film Simulation. In this case, I used Fuji XTrans III Velvia.