Nice shot!
My first thought was " Wow two moons, tatooine". I then noticed that you actually didn’t manage to get there. 
RT → tif → Gimp 2.9
Basic development in RT using a slight grading.
In Gimp I did exactly what I described here:
https://discuss.pixls.us/t/enhancing-local-contrast-vs-global-contrast/4872
Only difference is I applied the inverted overlay layer locally using the brush tool, trying to accentuate the bottom and the left upper part of the cave.
