This archive tracks four layers. A record present in 2 of them (M41, IND) is silent in the rest, and says so.
The Horus HeresyM30–M31
[RECORD LOST]
No record for this location in The Horus Heresy.
Age of the ImperiumM32–M40
[RECORD LOST]
No record for this location in Age of the Imperium.
The 41st Millenniumpre-Rift
imperium
Feral ocean world
Island chains, deep water and a human population that never got past sail. Reclaimed for the Imperium after the Damocles Gulf Crusade, which is a polite way of saying somebody else had it first.
Era Indomituspost-Rift
imperium
[RECORD LOST]
[RECORD LOST]
Nothing survives in the archive for Era Indomitus.
Position
Map frame: 866, 700 in the archive's 0–1000 disk space (core at 500, 500).
Distance from the core: 417 units ≈ 44.4k light years, south-east of the galactic core.
Height above the disk plane: -11.1 units — invented thin-disk jitter, deterministic per record. No published source gives any location a z coordinate.
System: Archipelaga System
Books set here
1 title in the reading tracker touches this record, 1 of them as a primary location. Titles link out to the tracker.
wh40k.lexicanum.com/wiki/Archipelaga infobox Class = 'Feral World, Ocean World'; https://wh40k.lexicanum.com/wiki/Planets_(List) agrees. Rendered feral, since Talassar already carries the ocean palette and this is the only world in the dataset canon types as feral AND ocean
gposlow
wh40k.lexicanum.com/wiki/Planets_(List derived: ) — 'Reclaimed by the Imperium after the Damocles Gulf Crusade'. Placed on the Eastern Fringe near the Damocles Gulf, which correctly puts it outside the Astronomican's reach