If I'm not mistaken, and I don't think I am, Ansiotropy is a particular kind of filtering that happens between MIP map levels, and FS2 doesn't MIP map by default. You can enable it in the SCP, but it will absolutley kill your framerate if you're not running the SCP on god's own box.
Before you go cussing out the SCP though, try to remember that a space sim is far more difficult to code a texture system then an FPS. A space sim has a basic draw distance of infinity - an FPS culls, and shows you a bit at a time. I think, anyway.
As it stands though, Ansiotropy will do nothing more then give you a slight increase to visual quality but slaughter your framerate.