A mod I am thinking of doing...

[AeoN2]

hmm... yes I didn't actually consider that... It does make more sense if it selects type at random and then finds a matching planet in secttype.txt... but if that is true then none atmosphere planets shouldn't be any rarer than others (unless there is special code again involving no atmosphere)...

Also you must consider that secttype and systemtypes are the only files that contain the different atmospheres, and I think that it's possible to add new atmosphere types here? If this is true then the new types wouldn't get selected at all if a special routine selects atmosphere...

--
AeoN2