The Celestial Orrery is a device located at the heart of the Necron Crownworld of Thanatos and is considered one of the galaxy's greatest treasures. It was crafted by the artisans of the Oruscar Dynasty long before the War in Heaven and is beyond any price in artistic value alone. This machine consists of a web of holograms and Necrodermis with the various tiny, floating, glowing lights representing a star in the galaxy. Each of these are recorded in an intricate matrix record that contains the locations of every star in the cosmos.
An act that snuffs out any of these lights leads to its physical counterpart undergoing a supernova millennia before its time that destroys all the nearby worlds that circle it. Thus, the Celestial Orrery is capable of immense destructive power but the act of destroying a star must be done with careful consideration as it would as it would upset the natural order of the cosmos that could create a critical chain reaction. Through further manipulation, any imbalance can be rectified and returned to proper balance though this can take thousands of years of constant precise micromanagement.
Despite this great power, the Royal Court of Thanatos see themselves as gardeners of creation who dispassionately use the Orrery in a precise but sparing manner. They believe in only pruning the galaxy to prevent it from becoming overgrown and wild. However, the power represented by the Celestial Orrery has led to the Oruscar Dynasty waging wars to protect the device from falling into the hands of other Necrons or aliens.