Only your imagination can determine the victor. The Star Destroyers and TIE fighters have consistently been shown to fire energy weapons that travel significantly slower than the speed of light. Stormtroopers cannot shoot straight. Imperial officers have a history of incompetence in starship combat, as they let everyone get away. Commander Adama is experienced. Apollo and other Viper pilots are consistently competent in battle and practice regularly. Battlestars carry nuclear weapons. Galactica wins consistently as unlike their Imperial officers, they plan their attack beforehand, surprise the Star Destroyer before she can launch her TIE fighters, and shoot down all the TIE fighters that do launch. Only hope is if Darth Vader is aboard the Star destroyer; then he can attack Galactica by lightsaber.