The vast cosmic reference planes like the galaxy were discovered in a gradual fashion. Men who studied the stars noticed that in some sections of the sky, there were many more stars than in other sections (Figure 1-C). In time it became clear that the area in which many more stars were concentrated extended on either side of the Earth, forming a vast belt or ring around the heavens in all directions. It was seen that this concentration of material was not a chance clustering, but a vast superstructure containing the majority of all the material, light, etc. in the near universe of our solar system. When a "best fit" circle was imagined and drawn through the denser parts of this belt (Figure 1-E), it divided the heavens into material located above and below this circle or equatorial plane, like a vast sheet of glass. A north and south pole were also projected (Figure 1-E) that "fit" the equator. The equatorial plane and the poles defined, there remains but one other step to perform: pick a point in space along this plane from which to measure longitude.

This is the most arbitrary step in the process of defining a new coordinate system, since all directions are equal along a circle. Astronomers attempt to choose the most significant and least arbitrary point along the equatorial plane of a system to be the zero longitude point. For instance, in galactic coordinates, the direction of the galactic center is now used as the zero point, and so forth. All of the above mentioned cosmic super-system were discovered in this manner.