The Rata Nebula was located in the Unknown Regions inside the core territory of the Chiss Ascendancy, the government of the Chiss species. The nebula contained the Rhigar system, which was linked to the Csaus system by the hyperlane known as the Path of the Houses and to the Csilla and Colonial Station Chaf systems by another hyperspace route.
The Rhigar system contained a planet of the same name, which was the location of a secret military academy operated by the Chiss military group named the Household Phalanx, a part of the Empire of the Hand. The nebula's bluish-green haze was visible from Rhigar's surface.
In 19 ABY, Jagged Fel, a Human pilot stationed at Rhigar's academy, noted that rumors about the supposed return of Thrawn, a Chiss Grand Admiral of the Galactic Empire who had died ten years earlier, had recently spread throughout the Rata Nebula. The rumors were in fact inspired by the existence of a clone of the admiral.
Behind the scenes
The Rata Nebula appeared in the short story "Red Sky, Blue Flame," which was authored by Elaine Cunningham and published in the seventh issue of the Wizards of the Coast Star Wars Gamer magazine, released on October 16, 2001. The 2009 reference book The Essential Atlas placed the nebula in grid squares E-9 and F-9.