A bullseye arc is printed inside of the forward firing arc of all ships. It has no inherent effect, but there are a number of upgrades that take advantage of it. For example, Marksmanship allows the attacker to change one hit result to a critical hit result, but only against defenders in the bullseye arc.
These arcs are a full 180°, using the hashmarks on the side of the ship base instead of the crossed diagonal lines. There is the full front arc and full rear arc
There are two types of turret arc indicators: a single turret and a double turret.