6-2 Turrets

The way that turrets open is connected to the position of the ship on screen (let's number them 1-4 from left to right).
Turret 1 opens when you are under Turret 3.
Turret 2 opens when you are under Turret 4.
Turret 3 opens when you are under Turret 2.
Turret 4 opens when you are under Turret 1.
This boss fight always starts with Turret 1 opening, so you can attack it if you move immediately to the left and shooting in the right moment