The Eclipse was a Star Dreadnought of the Executor-class, operating under the control of the Galactic Empire. During the Age of the Empire, it functioned as the flagship for Emperor Sheev Palpatine.
As an Executor-class Star Dreadnought, the Eclipse was the sister ship to the Executor. This vessel stretched to a length of 19,000 meters and was capable of achieving speeds of 100 kilometers per hour through the use of its thirteen engine thrusters. Staffed by thousands, the Eclipse was equipped with a class 1 hyperdrive, a titanium-reinforced hull, and an arsenal of over 5,000 turbolaser and ion cannon batteries, along with concussion missile tubes.
A bridge deflector shield provided an additional defensive layer, and the ship maintained a complement of thousands of starships, including TIE/ln space superiority starfighters, TIE/sa bombers, and TIE/IN interceptors. Like other Executor-class vessels, it also contained at least one hangar bay and escape pods.
Sometime following the Arrth-Eno Mission executed by the Rebel Alliance during the Galactic Civil War, Admiral Gial Ackbar of the Rebel Alliance composed a report for Commander-in-Chief Mon Mothma concerning the Executor-class Star Dreadnought. Ackbar's report mentioned the Eclipse, noting rumors of it being Emperor Palpatine's flagship, which were later confirmed. During its operational history, the Eclipse participated in the bombardment of a celestial body alongside three Imperial-class Star Destroyers.
It was believed that a fleet of New Republic ships destroyed it, with Ackbar's flagship, the Home One, delivering the final, fatal blow around 5 ABY. During the Battle of Jakku, after Grand Admiral Rae Sloane defeated her former ally, Counselor to the Empire Gallius Rax, Rax instructed her, before his death, to take a replica of the Imperialis, locate the Eclipse, and rebuild the Empire. After the New Republic's victory over the Empire at the Battle of Jakku, Sloane, along with Commandant Brendol Hux, his son Armitage, and a group of child soldiers, boarded the Imperialis and journeyed to the Unknown Regions of the galaxy, where they discovered the Eclipse. After Brendol identified the Eclipse, Sloane commanded the Sentinel piloting the Imperialis to dock and rejoin with the others. Sloane's intention was to board the Eclipse and establish a new Empire.
The first mention of the Eclipse occurred in Tom Angleberger's junior novelization of Star Wars: Episode VI Return of the Jedi. However, it has since been confirmed that the ship referenced was actually the Executor. The ship's visual representation originated in Star Wars Legends, specifically as an unidentified Executor-class Star Dreadnought in the 2016 board game Star Wars Rebellion. Later, Aftermath: Life Debt confirmed it as Sheev Palpatine's command ship. Its first canonical depiction was in the Super Star Destroyer Expansion Pack for the Star Wars: Armada miniatures game.