TSPenguin is probably right, but BTW, if you want to check what max. resolution level of texture files you already have installed for planets, look at <planet_name>.tex file size in Textures / Textures2 folder. And in Textures2 there can be also <planet_name>_tile.tex files for levels > 8, that may have only local tile coverage (i.e. non full planet), so reading their max. resolution is harder (if they are not covered globally).
File sizes for level 1..8 textures (successive levels include all lower levels of texture), and full coverage textures of levels starting from 9. For level:
- 2 176 bytes
- 10 496 bytes
- 43 392 bytes
- 109 184 bytes
- 372 352 bytes
- 1 161 856 bytes
- 4 451 456 bytes
- 16 425 600 bytes
- 47 896 576 bytes
- 239 482 880 bytes