Tau quadrant

The Tau quadrant was an area of space, possibly located in the Mutter's Spiral. When the Nestene Consciousness invaded Earth in 1999, the Seventh Doctor said that the nearest Nestene world was millions of light-years away in Tau. (COMIC: Plastic Millenium)

In Bernice Summerfield's time, the Nestenes still controlled a sector of the quadrant. (PROSE: First Frontier)