NGC 1309

Original fits and calibration files - Hubble Space Telescope
https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html

The image was made from 36 independent exposures (12 + 12 + 12 in B/G/R channels) from 2005, 2016, 2025. Total nominal exposure time — 12 hours. 
Stacking - noise-weighted means (`-weight=noise`) with additional winsorized 4/4 rejection. Noisier frames receive lower weight while still contributing to gap coverage.  Before stacking, a constant background estimated outside the galaxy was subtracted; a uniform numerical pedestal of 0.12 was added. Missing samples are marked as zero and were excluded from the mean, which was separately verified in the installed Siril. To enable weights, Siril additive normalization is used (`-norm=add`). After stacking, the pedestal and residual constant background were removed; negative noise values were preserved. Artifacts were removed by averaging (17 million pixels)
In PS, adjustment layers were used - curves, hue/saturation, color balance. 

Below is a video of similar imaging from NASA. The color palette (I like it more, but there are more artifacts) and the selection of original fits differ
https://esahubble.org/videos/potw2530a/