The Halo Zone is the name of the region of Segmentum Pacificus beyond the light of the Astronomican where Imperial Navigators guiding ships during Warp jumps are no longer able to sense its guiding light and are thereby forced to navigate blindly. Doing so in the Warp is extremely hazardous and most, if not all, Navigators will refuse to go beyond the borders of the Astronomican for this reason. Also, due to the difficulties in navigation, the time taken to cross a region is increased while also increasing the time differential between realspace and the Warp.
Lord Commander Solar Macharius attempted to continue his crusade into the Halo Zone, but his troops refused to go on into the unknown, possibly because they believed they would no longer be under the protection of the Emperor.
- 1: Codex: Imperial Guard (2nd Edition), [Needs Citation]
- 2: Codex: Imperial Guard (3rd Edition, 1st Codex), [Needs Citation]