Well, in standard game nearly anything glasses a planet in 1, 2 turns max... This is quite ridiculous but that's it !
Put a pair of "large" bombs on a Lt Cruiser should be largely enough !
After you clear the area, just about anything that can whomp on planets works.
The AI is pretty stupid. I was once able to clear a home world early in a game with a single ES mounting a DUC 2 I think. Pretty lame, but you have to ATTACK several times in a row maybe over several turns.
A human player never would have let you get away with that.
Custom weapon: Transphasic Torpedo. One shot one kill. Very expesensive though. Only a Base ship can carry one. And one only. Its destroyed after use.
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Creator of the Star Trek Mod - AST Mod - 78 Ship Sets - Conquest Mod - Atrocities Star Wars Mod - Galaxy Reborn Mod - and Subterfuge Mod.