The Galleon was a huge multicolored cloud about 2 million miles (3.2 million km) long and tall and over 100,000 miles (160,000 km) wide.
It orbited the Torilian solar system in a very slow orbit, taking over 4,000 months to complete a full revolution. The nebula shared its orbit with the Color Spray Nebula, but in the opposite position, so the two were never simultaneously visible from Toril.
The entire nebula was a wild magic region that wreaked havoc on spelljammer ships. It caused ships' gravity planes to shift quickly and unpredictably and caused magic items on board to buzz in a deafening tone. Once the ships left the nebula, these effects immediately ceased.
Rumors & Legends
Astrologers from Toril believed that the nebula had been placed in the sky by the deities of magic, both as a sign informing the inhabitants of Toril of the existence of spelljamming technology and as a sign of their blessing for its use. On the other hand, more isolationist astrologers believed that the nebula's wild magic properties served as a warning about the dangers of space travel.
Comets: K'Thoutek • King-Killer Star
Nebulae: Galleon Nebula • Color Spray Nebula
Far Realm-infested stars: Acamar • Caiphon • Delban • Gibbeth • Hadar • Khirad • Nihal • Zhudun
Other astronomical bodies: Caer Windlauer • Skull of the Void • Sargassos