i am not a pro to tell you whats correct or wrong, just my feelings, hence nothing personal/no offense
1st one: sky look good, perhaps you tried motion capture. increase AV and ISO. tell me 256 sec means what, if its in seconds, 4.2 minute is too high, so just try between 1/15 of sec and 2 sec, AV would be f/2.4 or high. dont let the darkness come into your pic.
2nd one: too dark apart from sky, try with large av, also control Tv and ISO. perhaps you also tried some adjustment in PS too (not know just feel) ....
happy shooting.