Veeery nice first post here

As njeneb said you did a very good job here with the scales. Just excellent.
I also like the sparse clouds, very good coverage and also the cloudfractal is nice.
The surfacing could use a little bit of work I think, some more color-variations would be nice.
Also, the rims of the craters could use some extra roughness/displacement.
Otherwise, very good work so far, looking forward to see more.
Cheers,
Martin