Septa Parisis is one of the moons of Perliss Mott. It was littered with the debris and wrecks of millions of different types of spaceships, ranging from thousands of years old to relatively new, and from many species. According to Rommie, the moon's surface is covered in metal filings that have been created from ships that been degrading on the moon for so long that they have been weathered down to rust by the elements and time. Septa Parisis is unique because it has been geologically engineered by nanotechnology to be hollow. The moon splits in half so that the Magog World Ship can be launched. ("Waking The Tyrant's Device")
The inside of the moon is hollow, and contains a Magog World Ship. The ship is powered by an Artificial star, but it must be ignited. To ignite the sun, the inside of the moon is lined by millions of mirrors so that when the moon is opened, sunlight is magnified and reflected to ignite the hydrogen powercells. The Magog World Ship was destroyed when Kroton tried to pilot it into Slipstream.