Hi! You're absolutely right! But i was planinig to make an animation with a spacecraft (battlecruiser from starcraft ) that is dangerously close to the planet! In that particular tutorial A.Alvarez don't mention anythink about scaling. I'll try at lower res when i'll have the time! Thanks!

And now i'll give you the link to the very hires maps of the solar system:
https://www.celestiamotherlode.net/catalog/earth.php

Some of them are DDS format.For those of you that are not use to it, it's a colection of mipmaps used in DirectX industries.You can extract the maps using a nvidia utility that's freely downloadable from nVidia site. I highly recommend Gnomon - Digital Sets Dvd's for the texture resolutions and tips.See ya!