Astronomican

The Astronomican is a psychic beacon located on Terra, which projects an astropathic beam 70,000 light years across the Milky Way Galaxy which human Navigators utilise to pilot the starships of the Imperium of Man through the otherwise unnavigable chaos of Warpspace. As the beam generated is psychic it exists within the psychic universe of the Warp. The beam can be psychically sensed from almost anywhere in Warpspace and is vital for faster-than-light travel since the mutant human Navigators use it as the only fixed reference point in the galaxy which is required for a starship to reach its intended destination when it travels through the Warp. Without it, the Imperium could not survive as an interstellar society as Warp travel would be impossible. It is uncertain how faster-than-light travel was done in the Dark Age of Technology before the Astronomican existed, though it can be safely assumed that a form of faster than light travel that is non-dependent on entering Warpspace and may be similar to Necron phase drive technology was used, or more likely that Warp jumps were simply unable to reach across as many light years as at present because of the lack of a fixed reference point. This is how the Tau's faster-than-light stardrive technology functions, as their vessels make shallow "Warp dives" across a much smaller length of realspace than current Imperial starships, and is probably how Mankind once operated as well.

It is the duty of the portion of the Adeptus Terra called the Adeptus Astronomica to maintain all aspects of the Astronomican, including training those Sanctioned Psykers who will power it. The "psychic light" of the Astronomican is beamed from Terra, from the Chamber of the Astronomican buried deep beneath the Himalazian (Himalayan) Mountains. The Astronomican is powered by the psykers trained by the Adepta, though it is the omnipotent will of the Emperor Himself that constantly directs this psychic energy across the depths of approximately 70,000 light years of galactic space. Although the Emperor does not provide the psychic energy of the beacon, only He has the psychic control required to handle such immense energy and direct it across the galaxy.

The psykers who power the Astronomican are recruited into the Adepts Astronomica through the division of the Adeptus Terra called the Adeptus Astra Telepathica. They are initiated into the Adeptus Astronomica as Acolytes, and are taught how to use their powers as well as the philosophy of the Adepta and the pivotal role it plays in the continued existence of the Imperium. Astronomica Acolytes learn the "Lore of the Astronomican". Some achieve a mystic state, gaining the status of "Chosen". It is these Chosen of the Astronomican who are eventually called to serve in the Chamber of the Astronomican. Here they fuel the Astronomican beacon with their psychic energies; as their powers are drained by the Emperor to fuel the beacon, the life forces of the Chosen slowly fade and they die, their lives a necessary sacrifice for the continued good of the Imperium. This psychic power is then directed by the mind of the Emperor across the width of the approximately 70,000 thousand light year range of the beacon. Because Terra is situated in the galactic west, the Astronomican does not cover the extreme Eastern Fringe of the galaxy. Warp travel beyond the Astronomican's reach is severely limited -- thus, it is the Astronomican's reach that effectively determines the true borders of the Imperium.

Destroying the Astronomican would most likely halt or badly cripple all Imperial Warp travel within the galaxy, effectively bringing the Imperium of Man to its knees, both economically and militarily.

The mutant Navigators, as well as other psykers of any intelligent species, can sense the Astronomican. It is described as a sensation of silvery light and a chorus of many heavenly voices, beginning first with a solitary voice and progressively growing into an angelic choir. It is suggested that "pious Space Marines" who can hear the Astronomican possess thw ability to fall into a meditative trance when they focus on it, perhaps as a result of their descent from the Emperor through the gene-seed of their Primarchs. Captain Gabriel Angelos of the Blood RavensChapter of Space Marines occasionally entered a sort of battle trance when he heard the Astronomican while fighting, improving his prowess in combat for the duration of the trance.

History
The Chamber of the Astronomican is located beneath the Himalazian (Himalayan) Mountains of Terra. It was built by the Emperor of Mankind as a focus for his fathomless psychic power. Originally, the Emperor fuelled and directed the beacon himself, projecting a beam of unimaginable psychic power and range through the Warp. How this was done in the early days of the Great Crusade in the late 30th Millennium is not clear, as the Emperor was off-world leading the war effort personally much of that time until he handed command of the endeavor over to the Warmaster Horus after the victorious Ullanor Crusade against the Orks.

During the Horus Heresy, the Emperor of Mankind's Imperial Webway Project drew more and more of the Emperor's psychic might away from the maintenance of the Astronomican as he sought to penetrate the corridors of the Eldar's Webway and claim it for Mankind, weakening its signal. Malcador the Sigillite suggested a compromise: the beacon would be fuelled instead by the psychic and life energies of 10,000 sacrificial psykers, freeing the Emperor to finish his great work. The Emperor approved the notion only with the greatest of reluctance, but also made it clear that it could be only a temporary solution, for he had no intention of killing a thousand men and women a day indefinitely.

Tragically, the Emperor would never resume his former role because of the wounds he suffered at the hands of Horus during the Heresy's climactic Battle of Terra, though his mind would continue to calibrate the psychic beam's frequency following his physical internment in the Golden Throne. Because of its vital role in the running of the Imperium, the Astronomican has great religious significance for believers in the creed of the Imperial Cult and the Emperor's divinity and it is also called the Light of the Emperor, the Ray of Hope or the Golden Path.

At the present time, the Astronomican is a complex piece of machinery powered by ten-thousand specially-trained psykers, whose life-forces are exhausted in a matter of months maintaining the beacon. Their ranks must therefore be constantly replenished with fresh recruits drawn from the tithe of psykers brought by the Black Ships to Terra to be used by the Adeptus Astronomica.

Limitations of the Astronomican
Warp Storm activity can affect the overall range of the Astronomican but it generally has a range of approximately 70,000 light years. As the galaxy is about 100,000 light years in diameter and Terra is approximately 25,000 light years towards the galactic Southwest, the Astronomican barely penetrates the Eastern Fringe of the galaxy; even less so in the wake of the arrival of the Warp-smothering Tyranid Hive Fleets.

Tyranid Attraction
The Astronomican's potent psychic beacon, unbeknownst to the Imperium's Adepts, is what is drawing the Tyranids to threaten the Milky Way Galaxy and all of the Imperium of Man. It is also drawing them, inexorably and irresistibly, towards Terra itself.