The great dome of the sphere that is the Astronomican sitting atop the Hollow Mountain on Terra.
The Forbidden Fortress, also called the Fortress of the Astronomican and the "Hollow Mountain," serves as the headquarters of the Adeptus Astronomica on Terra in the Himalazian (Himalayan) Mountains, and incorporates within itself both the Chamber of the Astronomican and the sphere-like structure of the Astronomican beacon itself.
History[]
During the Noctis Aeterna that marked the start of the Era Indomitus after the birth of the Great Rift, the Forbidden Fortress was assailed by the dark powers of the Warp at the Battle for Lion's Gate.
Many of the psychic adepts of the Adeptus Astronomica were driven insane while others of weaker temperament were possessed by Daemons now able to penetrate the veil of realspace around Holy Terra itself due to the temporary weakening of the Astronomican across the galaxy.
It was at this time that Inquisitor Erasmus Crowl and his retinue of Acolytes arrived at the Forbidden Fortress, and found themselves shocked that one of the most secure and vital installations in the Imperium had been so easily penetrated by the Archenemy.
The Inquistor's retinue was reinforced by Astartes drawn from the Imperial Fists Chapter, and together they cleansed the facility of its daemonic infestation even as the recently resurrected Primarch Roboute Guilliman marshaled the defences of Terra and defeated the larger daemonic assault on the Throneworld led by the legions of the Blood God Khorne.
Structure and Operation[]
Constructed on the orders of the Emperor of Mankind at some unknown point after the Unification Wars deep in the Imperium's past, the Forbidden Fortress was a remote and highly secret fortified compound on Terra, deep within the same Himalazian mountain range that was home to the Imperial Palace.
From the outside, the mountains where the fortress was situated appeared unaltered by Human hands, but the extent of the Forbidden Fortress had been constructed deep down beneath the roofs of the mountains and extended for many kilometres throughout the whole range.
The Chamber of the Astronomican itself was a massive sphere located within a single peak often referred to as the "Hollow Mountain." It had been resculpted into a great dome to form the upper half of the sphere which comprised the chamber.
The fortress' security was provided by Imperial troops clad in the grey uniforms of the Adeptus Astronomica, armed with Lasguns and clad in Carapace Armour like elite Imperial Guardsmen.
Access to the Forbidden Fortress was forbidden for any personnel not a part of the Adeptus Astronomica, and even members of the Adeptus Arbites or the Inquisition were forced to seek permission from the adepts of the Astronomican before they were permitted to enter.
Ten thousand psykers were chosen to serve in the Chamber of the Astronomican, using their life forces to power the great psychic beacon that the Emperor Himself calibrated and projected, though at the cost of up to 1,000 of their lives every solar day.
Yet more powerful psykers such as Space Marine Librarians and Astra Militarum Sanctioned Psykers were chosen to serve within the Forbidden Fortress, donning black robes to indicate their new status.
But the hunger of the Emperor was relentless, and in time even these notable individuals were often sacrificed to maintain the beacon, which was considered a great honour by all those chosen.
The Forbidden Fortress was surrounded by immense psychic emitters the size of cities which transmitted the psychic beacon of the Astronomican through the Warp across the galaxy, providing a pole star for every Navigator in Imperial space. Taken all together, these emitters were equal to the area of the Imperial Palace complex.
This highly advanced but slowly degrading technology was maintained by the tech-priests of the Adeptus Mechanicus. The power conduits which drove the Astronomican's apparatus led all the way from the Forbidden Fortress and its myriad emitters back to the mechanisms of the Golden Throne itself.
These gigantic cables that linked the Hollow Mountain to the heart of the Imperial Palace were placed within a trench that was hundreds of kilometers deep and was lined with defensive emplacements, Void Shield arrays and other equipment useful for the Mechanicus.
That this trench represented a singular point of vulnerability for the entire Imperium could not be denied.
Sources[]
- Watchers of the Throne: The Emperor's Legion (Novel) by Chris Wraight, Ch. 5
- Vaults of Terra: The Hollow Mountain (Novel) by Chris Wraight, Chs. 16, 18-20
- White Dwarf 140 (UK)
- Draco (Novel) by Ian Watson
- Inquisitor (Novel) by Ian Watson