I am working in a 3d globe based in a texture of 8000px , for some reason when I zoom a lot the map is not crips enough. I have changed in the editor tab the of the material the Texture Preview Size to the maximum, but still not cripsy.
if you zoom in enough the pixels are visible there is nothing you can do, if you zoom in and the image is fuzzy it may be that the image _is_ fuzzy. What happens if you do an equivalent zoom-in in photoshop (or whatever)?
Either way your texture may be insufficient, try the NASA textures referenced in this thread https://forums.creativecow.net/readpost/19/886116
The crispness of bitmap textures in renders is affected by the material channel's Sampling setting and the render AA settings. By default Cinema assigns MIP sampling when you load a bitmap in a texture slot. MIP reduces flickering in animation but it also makes the bitmap a little blurry. If you want it really crisp use Square sampling, or turn sampling off altogether.