Simple shot in Manual mode with 12.5 minutes of exposition. It was taken with a double filter (Haida ND3.0 {100 steps} and Haida ND1.8 {6 steps}).

After, It was processed with Darktable creating the basic canvas for AdobeRGB with the Logarithmic option for Unbreak input profile. Then, additional plugins like Tone Curve, Highpass filters (not water), Local contrast (not water), Lowpass filters, Haze removal, some denoise plugins, and others were applied.