Turrets
From X3 Wiki
Turrets are automatic attacking weapons.
Most ships bigger than an M3 have turrets.
Some M3s have turrets for missile defence. M8s usually do too. M6s generally have more turrets, and M7s have turrets all round excpet at the front, excluding the Panther which has a front turret instead of main weapons. M1s and M2s have turrets all round, but no main weapons.
The player can fire main weapons whilst flying the ship, and can use F1 to cycle through turrets. The ship cannot be controlled whilst firing a turret manually however.
In the Command Console for a ship various commands can be found for turrets, such as 'Protect Ship', 'Missile Defence' and 'Attack Enemies'. These help you to fine0tune what your turrets do in a combat situation.