Below is the newest version of the introduction for the Game Maps Rules Doc. As Haegan can attest to, I created a new Stellar Coordinate System that we are going to use in BTS!.
As always, comments are requested.
[2.0] THE GAME MAPS
Since the dawn of time as the species of the universe began to spread themselves to other star systems, they learned that stellar cartography was an entirely new level of mapmaking. It is easy for someone to imagine the two dimensional nature of a planet's surface and to draw boundaries across it. Space, however, is three dimensional. It does not fit well on the two dimensional maps frequently used by star nations.
Beyond the Stars! has chosen to make such representations 'top views' of the galaxy, and thus making the 'depth' of the galaxy the Z-axis. But such 2D star maps are, as one might expect, horribly inaccurate.
Just as space is 3D, so are the interstellar borders between Star Nations. A star on one XY-axis coordinate could be in the UST and another star on the exact same XY-axis coordinate, but a few light years away on the Z-axis, above or below, could be in the Numerian Commonwealth. Proper 3D political maps are, generally, giant globs of irregular-shaped masses, each with salients into each others space.
Sometimes you could come upon a straight line or 'wall' where expansion treaties or peace treaties from one or two centuries before had cleanly delineated lines of control. But, for the most part, the lines were irregular and misshapen, testimony to the struggle for rich and wealthy star systems amongst the empires.
[2.1] THE MILKY WAY GALAXY
The Milky Way is classified as a Barred Spiral Galaxy, which is roughly 13 billion years old. It is estimated that it has a diameter of 100,000 light years, a core thickness of 15,000 light years and a stellar population of 500 billion stars. It is divided into four quadrants, the Orion, the Scutum-Centarus, the Norma, and finally, the Sagittarius quadrant. The Galaxy consists of four major, Perseus, Scutum-Centarus, Sagittarius, and Outer, three minor, Near 3KPC, Norma, Far 3KPC, arms, and one spur, Orion.
The Perseus Arm has it's beginning on the northeastern end of the Galactic Bar, and is the closest arm to the Orion Spur, where Sol is located, and wraps through all four quadrants. Rimward of the Perseus Arm is the Outer Arm on the southern edge of the galaxy, which stretches through the Orion and Scutum-Centarus quadrants. The Orion Spur, mentioned earlier, is located between the Perseus and Sagittarius Arms. The Orion Spur give this quadrant it's name, the Orion Quadrant and straddles the Orion and S-C quadrant border. The Scutum-Centarus arm has it's beginning at the southwestern end of the Galactic Bar and winds it's way around the galaxy to peter out before it re-enters the Orion quadrant again. The Norma arm begins near the S-C / Norma quadrant borders and peters out before stretching into the Sagittarius Quadrant. The Sagittarius arm begins near the far side of the Galactic Bar from Sol and winds itself around until it peters out just before re-entering the Sagittarius quadrant. The two 3KPC arms are minor arms that begin and end near their respective sides of the Galactic Bar, Near and Far.
The population I stars in the galaxy's spiral arms tend to be young and towards the blue end of the spectrum, while the population II stars in the galactic core tend to be older and towards the red end of the spectrum.
Our local group of galaxies includes two very large spiral galaxies, the Milky Way and the Andromeda or M33, 2.2 million LY away, galaxies, and several dozen smaller, mostly irregular, galaxies that cluster around the two giants. The Large, 179,000 LY away, and Small, 210,000 LY away, Magellanic Clouds are satellites of the Milky Way, while the SagDEG is a dwarf erratic galaxy in the process of colliding with our own. Globular star clusters populate the galaxy's halo, and are concentrated near the galactic core. There are also migrating globular clusters located between the galaxies in intergalactic space.
Cheers, Thor