A Firework Launcher is required to use a Large Blue Rocket. (see Notes section)
Large Blue Rockets are crafted by engineers with a skill of 175.
requires that you launch eight Lunar Fireworks (color and size not specified) and two Cluster Fireworks (color and size not specified). Large Blue Rockets are a Lunar Firework, but they are not vended near the area of the quest, so are not a convenient item to use to complete the quest.
Unlike many fireworks in WoW, Lunar Festival Rockets (Large and Small, any color) require the presence of a Firework Launcher object on the ground in order to use the firework. These are widely available during the Lunar Festival only; near Lunar Festival revelers in cities and in Moonglade, and at other odd locations (there's some at the fishing dock in Orgrimmar). Firework Launchers are available year-round at the party at Saltheril's Haven in Eversong Woods. You can also spawn your own Firework Launcher for 30 minutes by using a , made by an engineer from schematics purchased from in Moonglade during the Lunar Festival. The schematics cost 5 . The Firework Launcher item does not bind; it has only one charge and is used, not equipped, so it is Consume on Use.