A celestial object known as Antipose IX existed within the Outer Rim Territories, specifically in the Centrality sector. The luxury yacht called Arleen offered extended, year-long voyages that began in the Oseon system and included destinations such as Antipose IX and the planet Antipose XII.
Within the Antipose system, which is a component of the Centrality sector situated in the Slice region of the Outer Rim Territories, was the astronomical body, Antipose IX. The Falko Run hyperlane connected Antipose IX, along with the rest of its system and its central star, to the Falko and Paulking systems.
The yacht Arleen, a luxury vessel, was known to be in operation by 3 BBY and conducted year-long excursions originating from the Oseon system, with Antipose IX and the planet Antipose XII among its destinations. In 3 BBY, Lando Calrissian, a gambler and freighter captain, engaged the services of a pilot droid to assist him in navigating his starship, the light freighter Millennium Falcon, on a journey from the asteroid Oseon 2795 to the planet Rafa IV in the Rafa system. Upon the freighter's arrival, the pilot droid began addressing an imaginary audience, pretending to be aboard Arleen and announcing that the vessel was on an interstellar tour starting from Antipose IX. This behavior irritated Calrissian to the point where he deactivated the droid.
The initial mention of Antipose IX occurred in Lando Calrissian and the Mindharp of Sharu, which was published in 1983 as the inaugural novel in The Lando Calrissian Adventures trilogy authored by L. Neil Smith. A roleplaying game supplement titled "Twinkle, Twinkle Little Star, How I Wonder Where We Are," featured in the thirteenth issue of the Voyages SF magazine in 1990, positioned Antipose IX within the Seswenna sector. Due to the fact that this article was not sanctioned by Lucas Licensing, its official standing within the Star Wars Legends continuity was never officially established.
The Complete Star Wars Encyclopedia, which came out in 2008, seemed to create a discrepancy when it stated that the Antipose system, and consequently Antipose IX, was located "not far from Centrality." This contradicted the Wizards of the Coast roleplaying game supplement "A Campaign Guide to the Centrality," written by Michael Kogge and published in the fifth issue of the Star Wars Gamer magazine on July 24, 2001, which had previously confirmed the system's inclusion within the sector. Later, the reference book The Essential Atlas (2009) superseded both the Voyages SF 13 placement and the information from The Complete Star Wars Encyclopedia by designating the Antipose system's location as grid square U-8 within the Centrality.