The Magical Convergent Cannon: Jupiter is a powerful weapon feared by all. When fired, the cannon releases a compressed beam of energy that wreaks destruction wherever it passes. One blast from the cannon was enough to completely shatter Erza Scarlet's Adamantine Armor, an armor renowned for its extremely high defensive capabilities, to pieces. Had the armor not intercepted the blast, members of Fairy Tail feared that one blast from the cannon would be enough to completely annihilate their guild and the surrounding area. Additionally, the Magical Cannon has enough power to significantly damage a Giant-empowered Makarov Dreyar, who, in that form, is well known for his enhanced strength and durability; a further testament to the overwhelming destructive capabilities that Jupiter possesses.
During the attack on Fairy Tail by the Alvarez Empire, Bisca utilizes Phantom's Jupiter in an attempt to destroy the lead ship. While it is blocked by Ajeel, the cannon beam refracts around his hand, destroying numerous surrounding ships.
The cannon in Phantom Lord's possession is a large, round wooden structure held together by many metal rods and bolts. The barrel of the cannon can be extended. The muzzle of the cannon is completely metallic, and is obtusely shaped. In the anime, Phantom Lord's cannon is portrayed slightly different. The barrel is slightly longer than the one in the manga, and the cannon itself is composed completely of rusted metal. In addition, aiding in the cannon's extension are four, long, metallic attachments hooked on to each side of the barrel.
The cannon in Grimoire Heart's possession is composed entirely of metal, unlike Phantom Lord's, and is shorter, with flat pieces of metal sticking out of the barrel at odd angles. In the anime, Grimoire Heart's cannon appears almost exactly like Phantom Lord's, with only one small exception: the metal appears newer and shinier, as opposed to Phantom Lord's old and rusty.
At some point Fairy Tail obtained Phantom Lord's Jupiter cannon and converted it into a more compact version of the original with the same level of destructive power. As before, four anchor cables connect to its base at its front. Emanating from the cannon's rear are four large bundles of cables connected to several smaller domed cylinders. Below the main body of the cannon are five cylinders that crank during the charging period. While anchored to a large base, the cannon is shoulder mounted by the user for aiming and firing.
Blue Pegasus later on installed the cannon into their Magic Bomber. Unlike the other cannons, this version is shorter and it does not have a barrel. It is composed of parts with varying width and a cone shaped tip where it charges and fires the charged up magic energy.
The power source for Jupiter is, fittingly, an extremely large, dark Lacrima, which is connected to by many cables, which in turn, are connected to the floor and ceiling of its station, feeding Magic Power into the cannon. In the anime, the power source for the cannon is relatively the same, except that instead of cables feeding the Lacrima Magic Power, there are four other, smaller, Lacrima that transfer Magic Power to the aforementioned larger one. The recharge time for the Magical Convergent Cannon: Jupiter in Phantom Lord's possession is fifteen minutes. The recharge time for the cannon in Grimoire Heart's possession, if one exists, is unknown. The recharge time for the cannon obtained from Phantom and now in Fairy Tail's possession is still fifteen minutes. On the contrary Blue Pegasus' cannon can be used immediately or it has a very short recharge time.