The Arcturus is a gun in Final Fantasy XII. In the original version, its license costs 80 LP. In the Zodiac versions, its license costs 100 LP and it can be used by Machinist or Shikari, although the latter needs to unlock Shemhazai first.
To make the gun at the bazaar the player needs to sell two Wyvern Wings, two Yensa Fins and a Salamand Halcyon. Wyvern Wings are obtained from Aeronites. Yensa Fins are obtained from Yensa and Bull Yensa. Salamand Halcyons are obtained from Salamand Entites.
Arcturus is the brightest star in constellation Boötes.