The Battlemoon was a lifeless satellite of Varn, transformed into a station for a superlaser dish. It had no atmosphere and was considered a moon.
Four Lambda-class T-4a shuttles could dock on the moon's surface, which also featured scattered pylons and many craters. The entrance to the base was situated on a cliff face and incorporated several security measures. A locked main gate with an external security sensor required Stormtrooper Corps-level ID cards for entry. Furthermore, a retractable bridge controlled by an Imperial officer on the other side prevented unauthorized access to the main complex. The facility comprised two levels. The upper level contained a blast door, equipment for the base, and stairways to the lower level. The lower level included two rooms. Each room had vital weaknesses; if both were triggered by seismic charges, the entire base would explode. Two Imperial officers, including a private, oversaw the facility.
Following the Battle of Hoth, the Galactic Empire repurposed it as a testing ground for superlaser technology derived from the Death Star. Luke Skywalker managed to board a shuttle from Varn to the Battlemoon, where he infiltrated the base with the goal of thwarting the Empire's scheme.
The Eye of Palpatine, as well as both Death Stars, were also called "battlemoons" because of their immense size.