The Tascollan Nebula was located in the Abrion sector of the Outer Rim Territories, and contained a single star.
During the time of the Great Hyperspace War, the Sith consort Valik Kodank built a Sith Temple, the Temple of Pain, in the nebula and she attempted so use some Sith artifacts to move it into the center of a sun there. However, her plan went wrong and the temple was placed inside an asteroid instead.
The bas-relief sculpture concealed the location of the Tascollan Nebula.The star on each of the uniforms depicted the location of a planet along the Corellian Run—Tynna, Cularin, Rodia and Ryloth.
Later, prior to the Clone Wars, the nebula was used by the Rodian slaver Gomalo, who left a carbonite-slab containing the frozen Jedi Knight Ji-Ad Sarain floating within the nebula. Gomalo created a bas-relief sculpture which marked the location of the carbonite. Sarain was later recovered during the period of the Clone Wars through the intervention of a group of individuals from the Cularin system.
Thaum Rystra later traveled to the nebula and became the apprentice of Kodank's spirit. He later lured a group of New Republic operatives there in 7 ABY.
The Tascollan Nebula was created for the roleplaying adventure Light and Dark. It was later retconned to be nebula that appeared in another adventure, Portrait of the Artist as a Young Rodian. Dan Wallace, in his blog post, spelled the nebula as "Tascallon."
- The Essential Atlas