This was destroyed by a group of Rebel insurgents in 3 ABY without their realizing the significance of what it represented. Meanwhile, the testbed for the Eclipse was turned into the battlestation Tarkin.
Intending to be part of the next generation of Super Star Destroyer, one was built by KDY while the other was built over Byss. The two existing Eclipse dreadnoughts began production early in the Galactic Civil War, around Year 0. It carries an armament of 540/54 Turbolasers, 340/34 Heavy Turbolasers, 100/10 Ion Cannons, a Gravity Well Generator and one of the most destructive weapons in the game with an Axial Super Laser capable of destroying any opposing ships with a single shot.
The Eclipse-class Dreadnought is a Super-capital Ship commanded by Imperial Remnant leader Palpatine in Era 3. Star Wars Empire at War FoC Thrawns Revenge Eclipse vs Executor