I have been experimenting with new skydomes but I am observing some odd behaviour. Even using a large texture (8k) I observe abberations in the sky texture(pixellation/banding) as if it has been mip-mapped or down sampled. Tried various model styles (icosphere, triangular) but the results are the same.
Using max64 converter exporting edf mesh, original texture is tga and looks fine in the 3D model.
Same problem many years ago and didnt find anything to solve it. So use original skydom and change the color of the sun, only thing could be done.
About the solution I have arrived at :(
Did a bit more experimenting and it appears to be jpeg compression artifacts (posterization levels) causing the problems - a big problem when nearly all web hosted images use jpeg compression.
Tried filtering the images to blend the level step changes but with the lighting model of the dome they are still very obvious.
It would appear the only solution are original images that have never had any lossy compression apllied.
For the sunny skydome texture of Most I used "flag" "nocompress" (http://docs.piboso.com/wiki/index.php/Track_Creation_Rules#Textures (http://docs.piboso.com/wiki/index.php/Track_Creation_Rules#Textures)), because it had very obvious steps in the gradients as well. I don't know what's the "clean" solution, but at least it looks better.
Thanks for the tip Steven, tried a couple of skies and it is significantly better than before :)