Nocturne is the central black hole of the Via Sagittaria Galaxy and the most populated body therein. The poles of the object is currently surrounded by large numbers of power collectors harvesting immense amounts of power from the body. Matter is thrown into the object and, as it falls, almost all of its mass is converted into usable energy in the form of x-rays. These x-rays are ejected from the poles in what is essentially a miniature quasar.
Energy-intensive processes such as synthesizing materials beyond iron (especially transuranic elements) are often conducted here due to the cheap energy costs. The area immediately around Nocturne is one of the most heavily developed areas in the galaxy, with large space ports for ships transporting material and several hundred embassies from nations around the Via Sagittaria.
The object is currently under the control of Sagittarium, one of the largest nations in the Via Sagittaria as well as the largest nation in the Via Sagittaria core. Numerous treaties allow for all nations in the Confederacy of Borealis to use the black hole with Sagittarium unable to restrict the usage without very specific circumstances (such as a national emergency, galactic-scale emergency, or other catastrophes). Nocturne has 1.52 octillion individuals living in the Birch Planet around it.
The Black Hole formed about the same time the Via Sagittaria did, 13.51 Gya. Throughout its history, it has merged with many other black holes. The largest collision occurred about 10 Gya. A galaxy a quarter the size of the current Via Sagittaria collided with the then fairly irregular Via Sagittaria Galaxy. This collision scattered billions of stars, creating the galactic halo, and caused Via Sagittaria to become a spiral galaxy, and significantly increased the mass of Nocturne. This influx of mass likely caused Nocturne to become a quasar.
It is estimated that at least a dozen civilizations have, at one point, colonized the black hole and used it as an energy source, however, the chaotic nature of the core destroys all but the most recent artifacts. These estimates are based on hundreds of surveys of nearby systems in the core yielding a dozen distinct civilizations. Archaeologists inferred that civilizations capable of colonizing the core worlds would also use Nocturne for power.
The Triumvirate Civilization first colonized the black hole in 17,520 BCE at the height of their civilization. It remained under their control until a fairly major collapse of the nation in 15,089 BCE. Nocturne would remain untouched until 908 CE, when the Yohjan government decided to build a military base on a nearby world, Thalia, while also begin construction of the first power-generation device around the body. This served to solidify Yohjan claim over the area despite several nations claiming it already. This action served as one of the many points of tension in the already fragile peace the Via Sagittaria was experiencing at the time.
When the War of the Final Transition broke out in 1,285 BCE, the base in the core grew from a small detachment of troops to a fully fledged military base. Nocturne was far too valuable to allow to fall into enemy hands. About one million soldiers were stationed on Thalia and a Wormhole Gate was set up leading to Aegyn. The gate went down in 0 CE as the Split of the Yohjan Confederacy began. The base was separated from the rest of the galaxy by over three centuries of travel time and a similar delay in communication. As far as the base was concerned, the Yohjan Confederacy was still winning the war and would eventually repair the gate.
Eventually, the soldiers realized that their home nation was destroyed. After a period of confusion, they eventually formed a government of their own, the Vaplein Republic. This nation would go on to control the central black hole and begin rudimentary power generation from the body.
When Sagittarium was first established in 20,567 CE out of a coup in Vaplein, it quickly ramped up construction of the power generators, which would later be named The Agorae. Using this power, it was able to quickly expand to occupy a large portion of the core. Using questionable methods to get the population to grow faster than it naturally would, Sagittarium became both the political center of the Via Sagittaria while also controlling the literal center of the Via Sagittaria. Nocturne would supply several million stars' worth of energy by the late 30,000's CE.
The most ambitious project of the Sagittarian government was to construct a shell world almost 65 million kilometers in diameter around the black hole. The surface gravity of the object would have been 1G, however, the escape velocity would be about 1% light speed and time would run several minutes slower per day than on the outside of the object. It would have been able to hold the entire population of the modern Aylothn-Sagittaria Group and would have made Nocturne the center of the Group. The object, simply called "Centralis," would have been supported by thousands of orbital rings. The black hole would have easily been able to power the entirety of the structure given enough mass was fed to the body. It would eventually become a proper Birch Planet. The project began in 21,709 CE, and is estimated to have taken almost 275,000 years to actually complete. Construction of the object ended with only a handful of orbital rings built when Sagittarium devoted more efforts to competing with the CoB. Economic troubles of the nation and a lack of interest caused the government to drop the project.
Nocturne continued to be relevant throughout the history of the galaxy. As Sagittarium joined the CoB, it powered experimental technologies not yet efficient enough to be used on ships. The first SICTIRIAD generator, for example, was created orbited Nocturne.
Already, the black hole accounts for five percent of the Confederacy's population. The influx of refugees from the War of the Ancients caused Sagittarium to have the highest population in the galaxy, and the demand for housing increased greatly. Terraforming planets was a slow process and, while preferred by many for solely aesthetic reasons, was simply unavailable. Instead, the Sagittarian government created trillions of cheap habitats orbiting Nocturne. Their power was ludicrously cheap as well due to the ease at which power was drawn from Nocturne.
As the war ended, immigration from the war-torn galaxy was still incredibly high. Immigrants from the Via Lacrimosa Galaxy were also common. The solution Sagittarium came to was abandoning the idea of creating habitats and instead creating a ludicrously large area for immigrants to live on. Sagittarium began the largest project ever started in the galaxy, funded entirely by how in-demand its real-estate would become. Across the equator of Nocturne, roughly an astronomical unit from Nocturne, exist a large number orbital rings. Above these rings, exist a platform complete with atmosphere, cities, and an ecosystem. The space above the poles have little habitation and is largely used for gathering energy. This band of platforms, currently several layers thick, is already home to almost 241 septillion inhabitants. The majority of inhabitants still reside in orbital habitats orbiting equatorially.